For sheer speed, go for Raptors, if capacity is not a big issue (I have 3 & they scream!). Otherwise, Seagates and Maxtors both seem to have a good reputation around here.
If you dont already have a SATA controller card, Firmtek & SIIG are about the 2 best ones out there, both in performance & price. I recently bought a SIIG 4 port card from OWC for $55.00
Newegg & OWC are both known for reasonable prices. But with xmas eve tomorrow, check the sunday ads for last minute HDD specials at your local retailers