I've had an HTC Desire for 18 months and it's about to go back for a hardware warranty repair (intermittent problem with radios and satnav getting 'stuck' ever since I got the phone) but even with that in mind it's been bloody awesome. If you don't like the stock apps for messaging/calls/internet/home screens you can replace with much better, free apps in a jiffy. I use it as a satnav in the car and since it comes with Flash I have barely used my laptop at home for the internet, ever since I got it. (I still use it at work though - it's not a total replacement.)
My mate has a Galaxy S and he absolutely raves about it, but he's a serious spod, I gather "normal" users hate it, but the S II is supposedly much better.
If you want a physical keyboard the Desire Z is a pretty good call and they should be quite cheap. But the on-screen keyboard is bloody good.
I'll be after a HTC Sensation next, although the new generation of Samsungs with flexible LED screens should be out next year. No idea of prices yet but they're supposed to be competitive at worst, could be a serious game changer.
iPhone is a good call if you're a technophobe with a lot of spare cash, as it "just works" but it'll cost you the earth. And you can't use the internet properly on it.
I'm on T-Mobile but I will be switching back to O2 sim-only as soon as my contract runs out. I'm not totally impressed, although it's been OK for me, but I have a few qualms that I would like to test on a different network for a while before I commit to another 2-year contract on my next phone.
