7200rpm WD Black is a good drive to go for, definitely faster than the 5400rpm drives they come with. Upgraded my old MBP with a 320GB WD Black 7200rpm drive, it was actually quieter than the original (obviously lower quality) 5400rpm drive, though the battery life suffered very slightly (about 15 minutes shorter).
Personally though, right now, no point in going for a 7200rpm conventional drive over a 5400. UNLESS you go for one of the new Segate Momentus XT Hybrid drives. These have an 8GB NAND Flash memory and a 750GB 7200rpm platter. The idea is the 8GB of flash memory stores your OS and all your frequently used apps on it (and it’s clever, so it learns what you use most, so it gets quicker after a few uses), but you’ve also got the 7200rpm 750GB conventional drive for mass storage that is also usefully quicker than a normal 5400rpm drive.
These Drives are £115 from ebuyer right now so snap one up!
Alternatively, a 240GB SSD is only about £130-150 these days if that’s enough storage…