Well, there's only two choices. Seagate and WD...
Samsung sold it's hard disk division to Seagate and WD bought Hitachi's hard disk division.
Toshiba doesn't make large drives as far as I know, and besides, I wouldn't recommend Toshiba in general due to their shafting of their customers in other domains.
So, given that there's only 2 options.. I would go for whatever is the cheapest, since, for a home server (and I assume this is going for a home file server rather than like a home computing farm...), the speed will be largely irrelevant.