In reply to climb the peak:
Havn't read all responses, and not an engineer but am a northerner who went to Oxford 05-08 so here's my two pennoth.
Oxbridge is hard but satisfying. People work and play hard, there are lots of hours in the day for you to fit multiple hobbies in if you want to if you're not chasing a first or watching daytime tv in your pjs every day.
I never felt uncomfortable or out of place there - there will be toffs but then there are at other universities too! They are just people and might be your new best friend. (The same goes for southerners in general which were a new species for me and are alright really *grins*)
University is a massive financial investment, you have to think about the return. If you just want the fun then why go to uni at all? Get any old job in a place you want to live for a few years and then think again about careers and studying. Or just have a gap year if you're sick of education and need a break. A levels are a pain, uni is easier in some respects.
Don't think that oxbridge degrees are only useful for certain career options, they are about getting skills and oppurtunities and yes, a certain kudos, that help you compete in whatever you want to do. Most of my uni friends are doing what they want, in a massive variety of sectors and locations. Lots of my school friends from home are not.
My career is not well paid, but fun, challenging and rewarding, thus competitive and hard to get into. My degree definitely helped me get into it in terms of raising my own expectations, my confidence, my communication skills and having a bit of paper from a particular place. Going out of my comfort zone geographically was a big boost too and opened up a new world.
You don't need a particular uni to get these things, but don't just write off Cambridge cos it will be hard. That is why there is kudos, because getting in is not the achievement, getting out the other end is (though drop out rates are extremely low!).
Why did you apply in the first place? Was it just expected by people cos of your grades? Does the learning challenge excite or interest you? Did you want a big name on your bit of paper? Are your family pushing you to go?
How did you feel when you went for interview, you must have got a sense of the place. Some people love it, some hate it. Either is valid, it's your opinion!
Uni is for 3/4 years, climbing is for life. Pick whichever you want and don't let anyone give you grief for it but base it on other reasons: not a false dichotomy of hard work/money chasing vs fun.