I have an N95 (on 3)
Pros:
* Superb screen. I mean really really nice. Clear, bright, vivid & large.
* Lovely "slide up" action, both ways (up = numbers, down = music controls)
* Incredible camera! (with flash + lense protection switch)
* Mini USB port + headphone jack for easy connections. Comes with lead to connect to TV to show videos/photos. Comes with car charger too.
* Uses any wifi network when in range (cheaper)
* Connects to anything! wifi, bluetooth, infrared, usb
* It's fast. The built-in browser is nice. Phone has flash / pdf support.
* Some excellent games available! (Jewel Quest II, Brain Training) and the 3D games are quite neat
* Drag and drop files from PC onto it easily.
* Sound quality is good, even from the built-in speakers - phone calls are crystal clear, music is pretty good but depends on what type - the speakers can't handle really booming tracks.
Cons:
* Battery life sucks. You won't get more than 1 day out of it. Especially in "poor coverage" areas.
* GPS is useless in a car without a hands-free kit.
* You'll need a bigger memory stick (I bought a 2GB one)
* D-pad can be twitchy
Personally I use my Creative Zen Stone for mp3 playback over my N95, it just has much higher sound quality and it only cost £30.
Cheers,
Rich
Never trust a computer you can't throw out of a window