I recently bought the first volume of the VFR Photographic Scenery from Just Flight/Visual Flight/Getmapping (bit of a joint venture) and it is fantastic. You can, for the first time, fly by visual references alone - it's very good quality.
FS2002 isn't up to the standards of the commercial training simulators (it's only £60 - you get what you pay for), but it's useful for exploring different types (there are literally 100's of free addon aircraft, some of which are better than anything you can buy - take a look at
www.avsim.com ), for practising instrument flying - you can set vis to 0 so you have to get used to relying on instruments, and for practising navigation - especially using navaids. I wouldn't recommend using it to improve flying technique - you could teach yourself some bad habits!
To answer your question (get there in the end), the majority of licensed airfields are present and correct, but visually disappointing as they mostly use generic buildings. Understandable, as there are something like 15,000 airports worldwide! I would take some time to play with the thing before you start getting into adding scenery - you might be happy with it as it is...
Have a read of the forums on avsim if you want to find out more...