yeah you really dont need to fill out a form. hard drive selection has nothing to do with the rest of your build unless its SSF or other specialty build. Sounds like your first build yea?
As I understand it, hard drive manufacturing industry is still recovering from the floods they had at western digitals plants in east asia. So, while this may be the worst time to buy a HD ever, it is still only a $20-40 price increase I imagine. (I have not looked)
Conversly, it is a really GOOD time to be buying SSD drives. Lots of competition and release of new technology has driven down prices especially on some smaller drives.
If I were you I would get a 90GB SSD drive and a Terabyte external hD later if you needed it.
If you absolutely must have a gigantic HD, just look at the solid brands like Western Digital on newegg.com. Im sure they have a few 500gb and 1tb drives available.