This phone is an excellent choice for those who want a Music Phone. The Micro-SD slot can be expanded to 16GB and the sound quality is superb. On the left side of the screen it has dedicated music controls making controlling your tunes a breeze, you can leave you MP3 at home after you buy this phone. The phone itself is good too, sound quality is clear and the buttons are big, it also provides good feedback so you know what you have pressed. Like other Nokias battery life is strong, usually a full charge last 4 to 5 days with moderate talk time. The phone is really compact and light, sometimes I forget if it's in my pocket and have to pat it just to make sure I have it with me =)
The downside is the camera, it's practically useless in low light situations. Even in moderate light there are still lots of image noise, you can get away with it a little bit by it being 3.2 Megapixels thus always giving you high resolution but at 3.2 it takes quite a few seconds for it to process the picture. Also since it's not a 3G phone, using EDGE for web browsing is a bit on the sluggish side.
The bottom line is if you want a stylish, light, practically phone with good battery life and music capabilities then you can't go wrong with this Nokia. If you want something more powerful with full 3G then shop for something else.
To clear thing up only two large US wireless companies uses GSM: AT&T Wireless and T-Mobile so this phone will only work with them. Overseas GSM is the dominate technology so you can easily use this phone outside the US.