If your good enough for Oxbridge, you go for that. Whether the teaching or IT facilities are technically better at some other palce isnt the point, its the reputation of Oxbridge. That Oxbridge are 1st and 2nd in the world for many subjects and Durham is about 83rd proves the point. On the point of getting a top (a really top) job, Oxbridge degrees give you a headstart no matter which way you cut it. Goldman Sachs, the world's biggest investment bank, only recruits graduates from Oxbridge. My brother got a Physcis degree from Durham and went into the city, he worked for many smaller companies to start off before luckiily getting a job with Goldman in investment banking. The point is, you can ultimately get to the same place if you work hard and are good at what you do, its just coming out of Oxbridge puts you a few years ahead of the rest if you want to get a top job straight out of uni.
On getting a really high paid job straight outta uni, it may not be such a straight forward good idea. My brother said Oxbridge graduates in Goldman get worked into the ground; many stay in the workplace for 48hour stretches. My brother works roughly the same amount of time (but does nicer things than pure number crunching like the grads), but now hes 27 it isnt such a big deal. If your straight outta uni at 21 and go to London, you dont want to spend your life's best couple of years outside of uni (like 21 to 25) suck in an office, even if it is nice to say you work for a top company.
Evenso, many of my bro's Goldman colleauges are all suprised someone with a 'mere' Durham degree is working alongside them. Many have firsts from Oxbridge and some other 'extras' from like Harvard or somewhere.
It is indeed all very snobbish and a bit revolting, but its just the way it is. I'm definately with CityTrader - its hard to get respect in the top jobs unless youve got qualifications from the top uni's