I've owned Western Digital, Maxtor, Hitachi, and Seagate hard drives.
For desktops, I like Seagate...mainly because they're very, very, very quiet. The Maxtors were the loudest drives I owned...I do a LOT of word processing and I like having a nice, quiet computer. The Maxtors in my old Athlon box were louder than my fans, hehe.
I'd recommend getting a Seagate with an 8mb cache @ 7200rpm - fast and quiet. And like Ken said, get a 3-year warranty if you can - the longer the warranty the better. CompUSA has had a deal on the 200gb Seagates for $99 a couple times, if you wait I'm sure you can find a nice deal on them. I'm using an 80gb Seagate in my main box right now, they run about $90 at CompUSA right now.
If you want speed, get a 10,000rpm SATA Western Digital Raptor (available in 36 or 74gb).
For laptop hard drives, I like Hitachi. Pretty quiet and quick.