Sachs or Valeo. Sachs is original equipment on BMWs (kit including pressure plate, disk and throwout bearing can be bought for 210 shipped); Valeo is an original parts supplier to a lot of manufacturers also, and can be bought even cheaper (I've seen them as low as 150 for the kit). You can't go wrong with either. On a stock, or near stock car, they will work perfect.
ps. If you want to know where to get the Sachs for that cheap, PM me, I really don't want to be posting it here because of our sponsors and what have you.