generally, London is an expensive city, with high property prices and many good bars/restaurants. Without knowing exactly what info you are after, its difficult to be specific, but if i had to generalise:
Cost of living: High, compared with the rest of UK.
Job opportunities: Good, better than rest of UK (i don't know anyone who came to London and has not found a job, and i don't mean working at Mcdonalds. No disrespect to people who work at McDonalds, but you know what i mean.)
Property prices: High, much higher that rest of UK. (£250k - £300k and up for a two bed flat)
Average job pay: Good, higher than the rest of UK. (i would say average pay in London would be something like £30k a year?)
Bars/Restaurants: Great choice, generally expensive, but you can find good and relatively reasnable pubs/restaurants. I would say average bill in reasnoable restaurant for two with bottle of wine would be £60.
Most foreign people (myself included) i know like living in London, most of Londoners i know want to move to suburbs.
[Edited 2006-03-04 20:10:48]