OK, so I'm biased, but, if you can get a job here, it has to be Scotland.

I live in Edinburgh and in no time you can be in the highlands on the UK's best, least cluttered roads. As a lover of wild, open spaces, I couldn't live anywhere else in the UK.
The major downside? The weather, it's pretty crappy, particularly this summer!
The upside? Too many to mention, but the main two for me are 1) the beautiful, wild mountains, lakes and beaches and 2) it has a FAR lower poulation density than the rest of the UK, with all that entails. Look at a map of the UK. England/Wales combined are a bit bigger than Scotland, but not much. Down there: 55 million people. Up here: 5 million people. It just makes for a much nicer place to live in my book.
This is not to say I'm one of those sassenach bashing jocks, my Dad is English, as are many of my friends, I have even lived down there. (Sheffield-not bad actually)
Edinburgh is a great place to live. Nice architecture and history, easy access to the north, nearby beaches and country, good places to eat, more culture than you can shake a stick at.
As for London, I have friends who live there and nothing (and I mean nothing) would induce me to join them!
Matt