Strike Up the Bandleaders : Commentary: If you’re gonna host a late-night talk show, you’ve gotta be choosy about the musician you choose for your sidekick.

Max, play me over . . . to bed!

Been feeling a little jumpy in your dreams lately? Switching to decaffeinated hasn’t helped? Maybe it’s all that late-night channel-hopping, the soundtracks for which these days seem generally designed to work viewers into a lather rather than lull us toward dreamland.

The partial exception is Branford Marsalis, who at least helpfully ends each “Tonight Show” with a sweet, lullaby-like theme. But on opposing channels, “Late Show’s” Paul Shaffer and “Arsenio’s” Michael Wolff are competing each night all the way through the end crawl to see who can turn the bedroom into the more-frenzied TGIF dance floor. Hey, Shaffer, how’re we supposed to get any REMs after all that R.E.M.?

And leave the channel on a few minutes after Marsalis’ soothing outro and your waning insomnia runs smack into the jumpin’-jivey “Late Night” theme by Max Weinberg, whose motto seems to be: Jitterbug, anyone?

Of course, Shaffer and Weinberg do their thing in Manhattan, where folks are just going out for the evening at 12:30 a.m., so no wonder they approach their work with the perspiratory, up-and-at-’em zeal of morning drive-time jocks.

Do we mind this pre-pillow, pepperoni-’n’-Jolt exercise in sleep deprivation? Not really, because if America loves anything, it’s a wacky sidekick from Canada.

And we have come to expect our bandleaders to be endearing comedic foils. It started sort of by accident with Johnny Carson, who already had a sidekick, but discovered he had two more who could actually get laughs and not just emit ‘em, in the form of heavily scarved hepcat Doc Severinsen and sartorially disadvantaged squarecat Tommy Newsom.

The late-night learning curve being what it is, most subsequent talk-show comics have figured: Why not just eliminate the middleman, as it were--i.e., Ed McMahon--and combine both roles in one Ubermensch of a straight man/musical director?

So far, Shaffer is the only superman who’s really Uber in all possible categories, though. If he served no other purpose than his ostensibly secondary one as comic foil, that’d be more than reason enough to keep him aboard: Imagining David Letterman’s nightly comedy without him is imagining a steady diet of Burns without Allen, the Lone Ranger without Tonto, Bush without Quayle, Fisher without Buttafuoco.

But musically, he’s the best conceivable candidate for the job, too. Forget versatility, which is one of his band’s obvious strengths. He and the CBS Orchestra, as they’re now known, are the one late-night group whose music is actually regularly a character in the comedy and not just a complement or counterpart to it.

The others have their merits, but must play eternal catch-up as long as Paul doesn’t quit his job. Following are subjective (but, of course, entirely accurate) assessments of the current crew of band-leading sidekicks, in order of preference:

Paul Shaffer--He was funny well before hooking up with Letterman, proving his mettle playing the recurring part of Don Kirshner on “Saturday Night Live” while still a keyboard player on that show in the late ‘70s. His greatest artistic triumph outside the Letterman sphere, though, remains his cameo as Artie Fufkin, the overly penitent record company promo man, in “This Is Spinal Tap.”

A lot of Shaffer’s humor on Letterman’s show(s) over the years has likewise involved the keyboardist playing himself as a lovably unctuous “cat” with an inordinate love for this business that we call show. This worked well in the early years, and fortunately, he did tone down the Vegas-y rhetoric about the time it was in danger of getting seriously old. His persona now is a combination of that insider guy with a droller, more Jack Benny-like persona. Shaffer laughs at Letterman’s jokes in the McMahon tradition, but manages to seem suppliant without being sycophantic.

With the switch in networks, Shaffer expanded the band from a quartet to a six-piece, with the only immediately noticeable effect being the rearrangement of the theme song with jolting, multi-synth power chords. As before, they can play with anybody from Springsteen to Tony Bennett, and the program’s ever-controversial policy that all musical guests must be backed by Shaffer and company makes the Letterman show unique among TV pop showcases.

Possibly the best thing about Shaffer’s presence, though, is the way his instrumental snippets or “bumpers” typically comment on what’s going on on the show, in ways that sometimes only music buffs will recognize. Each Top 10 list is followed by riffing from a song whose title somehow relates to the topic in question, sometimes obvious (“Top 10 NASA excuses for losing the Mars space probe” is succeeded by a few bars of “I’m Losing You”), or sometimes a little subtler (“Top 10 things we love about CBS” gets “Eye of the Tiger”).

Only points in the debit column: Those suits. Sometimes Mr. Blackwell does know of what he speaks, Paul; wake up and smell the Rayon.

Branford Marsalis--Jay Leno clearly wants to be both the populist and the class act on the dial at 11:35. For the class, he’s imported one of the most beloved jazz cats in America. The decidedly uncomedic music here is very much intended as counterpoint to the silliness of the rest of the show: It’s your full-service late-night stop.

It’s not a terribly appropriate match, but certainly there’s plenty of historical precedent for humorists and jazz orchestras sharing bills, without expectations that the music should somehow have to play a comedic role too.

And Marsalis’ “Tonight Show” orchestra certainly couldn’t be a more appropriate modern successor to Severinsen’s. Occasionally he or his charges will sit in with the musical guests--affording such luxuries as the sight of Marsalis sitting in on sax with They Might Be Giants--but he doesn’t have to lose his dignity by jamming with, say, Billy Idol.

The original selections are often terrific, if--as the common lament goes--too truncated. You don’t mind hearing just a few seconds of Shaffer’s band playing the opening riff to “The One I Love” or “Synchronicity,” but you do feel a little cheated getting just snippets of Marsalis’ more expansive artistry.

All that’s really lacking here--and it’s not a fatal flaw, but an unavoidable one--is any extra-musical chemistry. Marsalis was picked for the job in part, no doubt, because he’s so funny in person, but after a year and a half, his natural jocularity still hasn’t really translated to television. Whether acting in the occasional skit or just kidding with the host about their weekend sports bets, Marsalis looks vaguely embarrassed even now whenever he’s called upon to participate in the funny stuff.

Max Weinberg--This, too, is an example of counterpart casting: Conan O’Brien’s comedy is typically so willfully childish that it seems to be up to the classier, traditional stylings of the Max Weinberg 7 (along with the host’s three-piece suits and the library-style set) to remind viewers that, yes, these are indeed sophisticated grown-ups play-acting here.

On the plus side, erstwhile E-Streeter Weinberg has concocted what, in our view, just barely squeaks by Shaffer’s time-tested theme as the best instrumental opening in late-night: a sort of jazzy “Flight of the Bumblebee” journey that’s a dazzlingly inviting accompaniment to the show’s ‘50s-styled opening montage.

The same sort of stuff predominates throughout the show. No recognizable pop tunes here, no synths, no major attempts at versatility--just blaring, bold big-band riffing that’s heavy on the horns, as well as (of course) more reliant on thundering drum-kit intros than anything this side of Buddy Rich. Who would’ve figured it--Louis Prima-inspired barrelhouse jazz for Generation X?

On the minus side, while this freshly anachronistic approach is definitely a bright spot in late-night right now, its one-dimensionality may well seem tiresome a year or two down the road, if O’Brien’s version of “Late Night” ekes by that long.

Interestingly, this is the one late-night show that’s chosen to go with a model akin to Carson’s old one, having a sidekick on the couch separate from the guy in the bandstand. Weinberg gets to talk only occasionally, and shows up in the rare skit, like the embarrassing one parodying his former boss, Bruce Springsteen.

The only major signpost of personality, then, is the big, goofy grin plastered on his face every time Conan exhorts him to “Play me over, Max.” Did Weinberg go to school with “SNL’s” G.E. Smith, or does producer Lorne Michaels make them both do that?

Michael Wolff--Like Weinberg, Wolff wasn’t hired to be a chat master. He doesn’t even get the close-ups; he’s just that slick-looking guy behind the keyboards (not to be confused with Starr Parodi, that fabulous babe behind the adjacent keyboards).

But on the compatibility-with-host meter, the Posse scores a perfect 100%. Wolff and his bunch even humiliate themselves by egging the “Arsenio” crowd on in fist-pumping motions every night, without anything so much as redemptive, Marsalis-like looks of guilt.

Chops are in considerable supply with this crew, which expertly churns out your basic high-powered lounge jazz-pop fusion, maintaining an energy, if not exactly actual style, that speaks to Hall’s targeted hip-hop generation. But the funk is sooooo 1986. Typical bumper music choice: Steve Winwood’s “Higher Love.”

Much like the show in general, the Posse does what it sets out to do well--that is, bark, and not bite.