MS Comfort Curve is the keyboard i've found myself speeding along on the most, and its around £13.
I now have the Ergo 4000, which i'm quite a bit slower on, but i find i'm getting better over time.
Both are great for typing with.... well i find that when i think i've hit a wrong key i generally havnt, and i think the curve and layout is part of the reason, keys feel laid out more naturally to where the fingers where to want to go, well i suppose thats the point of an ergo keyboard, lol...
Strange really, about a year or two ago you would never caught me near an ergo keyboard, but now i can't stand typing on anything less.... i did find starting on the comfort curve made the transition much easier though as that less curved/ergonomic, and the keys are laptop style and much easier to hit.
Everyone has there own preference though, but for £13 or so you've not got much to lose giving a comfort curve a shot.
As semi-pro said, MS keyboards seem great for typing, i've always used MS kb's since i first got one as a present, which they stop producing and i destoyed it...

(RIP Internet Pro Keyboard - One with the extra buttons and usb ports)