I know it's been metioned before but LBC213 made a really good point - it's personal traits and how you come across that matter the most. the only time they're going to look at the uni you went to is when you send in your CV - once you're through the door even if you went to cambridge it wont matter a slight bit.
Ive a mate at university college dublin (and what kind of rep does THAT have with the layman) who got a sweet summer internship in asset management somewhere in mayfair and got asked back again for next year. My dad went the same place but still managed to get a offers from big firms to do his final books (some accountantcy thing), mainly cos hes got the gift of the gab.
interview skills are were its at when it comes to landing good jobs, IMO.
And **** any1 who wants to be at oxbridge over imperial, imperial still turn people down every year, runs oxford close in the tables and tops out on lots of subject specific tables. I didnt apply for cambridge (would have been a nice boost to know i could get in tho), and i dont regret it. IC was my no1. and I dont think we'll have problems getting jobs afterwards.