Buy whatever's on sale over 300GB. The important part is the software that does the backing up.
There's a dumb way to do it, which is just simple copies of your 32GB, so in 300GB you get 10 copies, in 1TB you get 30 copies.
The better way is to not duplicate the common parts of these copies and each time record just the differences to the last backup. That way you can have daily backups of your music for years that won't take more than 50GB and are fast to make too. Unfortunately I don't know anything about backups in the world of windoze, so somebody else will have to guide you there.
If you are going to just keep it at home and don't care about portability the larger 3.5" form factor will be a lot cheaper than the 2.5" portable that Jeff bought. Also I'd bet your computer doesn't support USB3.0, so if I'm you I'd buy a 3.5" USB2.0 hard drive that the vendors are trying to offload since the computer can't take advantage of the faster 3.0 interface anyways, and when you buy a new computer that supports it you can buy corresponding 3.0 drive for much less money than you can buy it today.
may be something like
http://www.tigerdirect.com/applicati...0597&CatId=136