Stay the fuck away from samsung. Trying to use their UI is like trying to smoke ash. Worst fuckin thing ever.

Personally, I am a fan of motorola, the UI is simple and makes sense, and is fairly consistent among phones. I have an E815 and love it, I can tether over EV-DO and get ~350k near any cities, it's never dropped a call on me, it works like it should really. It's a bit large though, but you could probably pick one up for $100 or less. It's also open as shit, so you can easily make your own ringtones/etc.

I wouldn't buy any of the current gen phones, they are all tied down like a fuckin' kidnap victim. You really don't own what you own, it's awful.