I made a S754 and S939 system and compared them when I was building my setup.
Turns out they weren't too entirely different in price. It's definitely one of those things that, you can gain twice as much with a few extra bucks.
<-----Maxtor fan. Some of these folks on here like to flame away when they yield absolutely no experience with certain parts. Maxtor HD's seems to be the bandwagon for spouting off unwanted opinions here. I own a Maxtor, and I have no problem. Bottom line. Seagate and WD are nice too.