I built my bike up with a budget of £1000 by ordering everything separately and putting it all together myself, got decent range of parts as i got to choose everything within budget and didn't have to put up with any OEM stuff, i'd recommend it, i used an outdated spreadsheet from "head to the hills" shop in surrey -
http://www.head-for-the-hills.co.uk/custom-builds/custom_builds_examples.htmspent some time online looking at reviews of each part, then went looking for deals on the parts i chose and built it on paper first !
then you get to go shopping !!!
I used Chain Reaction / Merlin / tredz and LBS
but beware.... i broke my budget my £200 as i got sa little carried away and i still want to get a bashing / chain device and a lime green frame protector from lizard skins... i'm such a tart !!