I had both a Sony Ericsson K790a & a Nokia 6500 Slide. Been with Cingular/ATT for about 8 years, and was buying a new unlocked GSM phone every 6-9 months. I haven't felt the desire to buy anything since I got my 2G iPhone 18 months ago....except for a newer iPhone which I'll get this summer assuming significant hardware improvements.
Sanyo Kantana, basically some POS from Sprint that was supposed to compete with the Razr. In other words, a piece of garbage, but I still use it as my back-up alarm clock (iPhone is too easy to shut off alarm - I can do it in my sleep).
Samsung Blackjack - sometimes I miss that phone. If I were to wake up tomorrow only to find iPhones had all been a dream, I'd go buy another Blackjack.
It had a little joy stick type lever for navigation, but mine would only scroll up. So I had to think backwards for everything I wanted to select. It also had a useless camera on it. The pictures it took were blurry and postage stamp size @ 72 ppi.
It was so bad that it kindof became a novelty item. I would show off its faults to my friends to get a good laugh.
BlackBerry Curve(8330 I belive?) with Verizon. I'm not going to lie, I miss it dearly at times. It out did the iPhone in email and as a PHONE hands down!
SHHHHH!!!! Dont tell anyone I said that. Most of my friends have BB's and I defend my iPhone like crazy!!!!!
I had a Vodafone 715 when the iPhone was released here. I've since switched to a Nokia 6275i (CDMA; if you're on a GSM network then you may know it as the 6234).
I had a Blackjack 2. Before that I had a Samsung A737, and before that a Motorola Slvr. Before that was the Nokia 6102i, of which I had 7! Piece of crap Nokia.
A Motorola RAZR V3i (the phone that even Steve Wozniak prefers over the iPhone, as he once said in an interview). And after having used an iPod Touch for more than a year and having experienced Apple's extremely proprietary and locked-down DRM platform, I really don't want an iPhone anymore.