In reply to Sam Wallace:
Going entirely by personal experience and preferences, YMMV, this is how I might approach it -- prices taken from a sampling of independent climbing shop websites, for purposes of rough example:
Set of nuts -- the Wild Country rocks are classics, and you can get a set of 1-10 for about £65, less if you're happy with the non-anodized ones
at least two screwgates -- I like the DMM Phantoms, and a couple would be circa £29
at least one 120cm sling, nylon's cheap and works fine (though the aramid pokey slings are awesome when you want a second), £6.50
four wiregates -- Needlesports has the Spectres at 4.99, so £19.96
plus two skinny 60 cm dyneema slings (£17.98 total), use them with the wiregates to make your own slingdraws
some cams -- I like the DMM Dragons, and the extendable slings lets you get away with fewer quickdraws, but your mileage may vary; some people hate the lack of thumb-loops. Look for a bundle deal covering the mid-sizes, then you can add outwards from there. A green-red-yellow bundle looks to be about £149.
That takes you up to £287.45, so add a nut key if you've not already got one. *g*
It's not a complete rack -- you'd need to start saving for more cams, for a start -- but I'd say it gets you off to a solid start.