In reply to Dangerous Dave: Thanks Dave. I thought v brake wheels were significantly lighter for same cost but your comment made me look again and I may be wrong! and like you say, where the weight is makes a difference. Think I've been looking at wheels so much i can't see the wood for the trees!
I guess the real reason is the cost. My budget would be in the region of £100 per wheel and ideally as little as possible for decent brakes, but my basic understansing from reviews etc is that cheap discs are rubbish and will need lots of maintenance and setting up? Having always ridden v brakes i'm not too clued up on this.
So i guess that as i want to get riding soon as, i was thining of getting a v brake rear to last me until i can afford the disc front wheel with brake and then upgrade the rear at a later date. but maybe i'd be better getting the rear disc wheel and a cheapo disc brake and upgrade this at a later date.... decisions decisions!