only one HD? If you're gonna spend $200 on hard drives, you'd get the most space if you get 2x 200GB (which will run you a little more than $200). or 2x 160GB, which will be slightly less.
Other than that, I think you'll find there are as many HD manufacturer preferences as there are people on this forum. Personally, I'd go w/ Seagate for their 5yr warranty (actually, I just did... purchased 2 of their 200GB SATA drives) I've also had a lot of luck with Western Digital.
Right now, I'm pretty certain the sweet spot for $/GB is are the 200GB drives.