There are so many ways of cooking with steam -- collapsible baskets, bamboo steamers, double-boiler models. All get the job done.
But to me, none compares with the electric Oster Food Steamer. It's been a Test Kitchen workhorse for years: The clear plastic steaming bowl is big enough for a whole chicken or large piece of meat, and lets you monitor cooking without lifting a lid (and letting steam escape). You can see the moment when mussels open and shrimp turn pink. You can steam a whole meal at once in its stackable bowls. It steams rice beautifully, and reheats soup and stew without scorching. We wouldn't be without it.
The Oster Food Steamer is $39.99 at Costco, Macy's and other retailers.