If you work in city banking then of course you will have had to do a job specific degree at a university recognised by that sector. Thats no different to going in to medicine or law. However, not everybody has the means, grades or inclination to do this and, without entering in to a debate about universities and courses - in some respects anything is better than nothing.
I know plenty of people who are in good jobs earning good money who have qualifications completely unrelated to their profession.
I think its easy to be elitist about further education. My advice would be do something that will interest you enought to stick to it, is at least somehow likely to help you in the job market (ie not a degree in David Beckham if they still do them!) and try to keep your uni costs down.
When all is said and done I feel fortunate I am not having to make the difficult decisions that some posters are at 18/19/20 years old. Its a difficult tiume for anyone making their way at the moment.