If you need fast SATA drives you can't beat the Raptors, they smoke everything else even some scsis. They cost a bit more but are worth it if you need fast access time. I run two in Raid1 at home and XP is lightning quick. For a game server it might be a touch of overkill but if you budget can fit them in, you'll be happy.
My data drives are Seagate or WD 200GB+. I have 3 of each in my system, all the seagates are great and the 5 year warranty is awesome. The WDs are pretty good too, although I just had to change one because of noisy bearings.
The seagate will be fine, one thing I forgot to mention is seagate and some WDs get very hot if they are in a small case, if it is only one drive then you will probably be fine, but if there are 2-3 in a mid tower case it is best to have some active cooling on them. Put them in 5.25" cooler bays, decent ones are only like $20/each and give you temp readouts and make a huge difference in longevity.
Of course decent UPS power backup is essiential too, if you are colocating this box then that should be provided but if you just going to run it 24/7 at home or something you should get a UPS to protect it. I would recommend spending the extra to get the 'Smart' ones that filter the power, not the cheap ones that just hard switch over to battery.