iPhone 3G, 8GB.
Why? Because after a couple of months of reading technical and user reviews, play-testing with people's phones, I finally decided it would suit me quite well. It does everything I need out of a phone, plus a heap of stuff I didn't know I'd find bloody useful.
I was once one of those sad bastards that got shitty about everyone and their cool phones by saying "If I need a camera, I'll use a camera! And if I need music, I've got my mp3 player! And if I want to play games, I've got a PSP/DS!" but then I realised I couldn't be arsed carrying around all this crap in my bag, so I slimmed down to the Nokia N95, which was a great little beast.
In the end, the iPhone was a natural choice. In retrospect, though, the camera could have been vastly improved.