Just do me a favor, if your previous phone sucked, just look at which part of it sucked, and don't buy that again. Stop rewarding crap that doesn't suit you. I mean, we've managed to punish Motorola for tricking us into buying that buggy RAZR POS just because the outside looked cool and then taking that design and slapping it on everything till the RAZR looked as exclusive as a piece of toast, to the point that Motorola is cutting everything and trying something completely different in their labs in Chicago. That is good, people.
Did you hate the Windows Mobile experience? Don't buy the next one! It's been 7 years and it's still not getting seriously any better! Sony-Ericsson and Samsung can't really improve it with a neat new shell, they can't fix whatever makes it lock up spontaneously once in a while (like, say, every day, for some people. Or when they receive a call). You didn't like it? Don't get another one! Let someone else surprise you.
Try things in the shop. If something annoys you there already, it is not going to get better when you have to do it 50 times a day (like scrollbars on a touch phone, geezus christ what are you thinking Nokia 5800? Are you on drugs? Was your mommy on crack when you were being gestated in Espoo, and is that why you are some mongrel bastard UI of a finger-touch and a stylus phone?). If someone has to show it to you in the shop, you're going to forget once you are outside of it. If something on the screen doesn't clearly indicate with words or images that you should swipe or click or touch or dial or arrow here, it never will, and you won't remember two days from now. You're going to use that thing 60 times a day or so, so make it sure it does what you want it to do.
Don't make the same mistake over and over. Make these manufacturers work for your patronage, even if the phone is offered 'for free' in the shop. It's the only thing that will get them off their ass. Free stuff will still annoy the hell out of you three months from now when it still don't work like it didn't work in the shop and you knew that was a problem already.
Just don't settle without having tried.