had a 9000 for a 2nd phone for 4 months and still really like it. Bold 9900 is my favorite BlackBerry so far though, love this thing and i'm not even on 7.1 yet!
I don't have any past BlackBerries (or else I might be inclined to fool around with them - even just turn them on and take a stroll down memory lane); but I do get out my Nokia C3 (my baby) and play with it sometimes. I still have some old text messages on it that I scrolled through. It's nice looking back!