I'm from a very middle class white town but even i noticed that sussex is very very white, there are very few ethnic minorities. It doesn't really matter, but it does surprise me a bit what with it having such a reputation for being very laid back. Also because so many people come from london, and south london in particular i've found... just an observation though!
Also, I agree about the rent - 2nd and 3rd years aren't going to be cheaper than 1st, unless perhaps if you were in phase II, although i know halls rent is going up and i don't know new prices. But average in town is £72 i reckon, excluding bills. Ours is discounted over the summer and some of my friends have leases that start in september (although i wanted ours to be able to pop down over the holidays!) but also remember you're going to be paying to get the train/bus into uni as well.