Here's the last on I bought. . I've gotten 4 drives from there. The prices are good, shipping is good. You can save if you don't need the combo interface and just go with USB 2.0 or firewire.
As for actual drives, I always stay with trusty Maxtor in any of my builds. I will use a WD drive if I had to. I stay away from IBM because of known issues. Samsung drives just plain suck - too many failures, too loud.
Maxtor is also great to deal with on RMA issues. WD is pretty bad if you have to call them for a replacement.
i would say firewire though i guess if you only have usb2 then thats ok. as for brand, what really matters is what brand the drive in case is. i liked those peerless thing but they discontinued them