From the early Golden Age of Blackberry, circa 2003, a classic of pure functionality: the keys are right where your thumbs expect, the size is perfect for both two- and one-handed holding, the scroll and click wheel lets you move through lots of email and then click on the ones you want and the phone feels great when held. What does it do? It gets your email and tells the time. Anything else? Not really, though it was the first BB with an integrated phone.
Note: I'm not 100% sure that this is the 6210. If you have other info, please corred it on Flickr.