I have 3 WD drives- 2 of them are 250gb and about 1.5 years old...the other is 160gb and about 3 years old. Neither of them have had any problems. I also have a 60gb Maxtor that's about 6 or 7 years old, and while I don't use it anymore it still works great and I've never had any problems. Although I don't have any personal experience with Seagate, I know them to make quality drives. The only reason I chose the WD drives was that they were the cheapest.
everybody has their own preferences but seagates generally have the better reputation. oh, they also stand by their 5 year warranty for consumer drives. they have to be either crazy or confident their stuff will last at least 5 years
If I'm not mistaking, Quantum is now Maxtor's "high-end" drive model. They're a bit less common but you may care to consider them. As for common drives, I've had the most problems with Maxtor and the least with Western Digital. Seagate is still one of my top picks, but I had problems with their drives a few years ago as well...