Loved my Nokia 7110
The Nokia 7110 had the best ever single feature in it's spring-loaded slide-down cover. I used to spend hours just hitting the button to open it, then sliding the cover back into place with a lovely chunky click, pretending I was a cool haxor dood in the Matrix*. Probably spent longer doing that than actually talking on it. I was sure that the spring would eventually break or pop out, and sure enough it did, but only after several years of abuse and after I had bought a new phone anyway. Nokia had some good build quality back in the day.
(* Yes pedants, I know that was a mocked up version of the 8110 in the film, but no-one could tell the difference down the pub.)