The best balance between performance and price is the Seagate Barracuda XT HDD's. IF you read some reviews they are really quite fast for an HDD. And you can get a 1TB for 59.99. Thats what I paid for mine.
If you want speed and space then go with a 500GB Velociraptor 10,000 RPM HDD. They cost about 135$. You can get a 250GB for 98$. They are the single fasted HDD that there is. About twice the speed of the average HDD. I find it absolutely pointless to have so much speed on a DATA drive. I even keep all my games on my HDD. I find everything to be pretty quick on my Seagate.
I have a 120GB Kingston HyperX SSD for my OS and programs, a 64GB mSATA Crucial m4 for additional programs and games often played, and a 1TB Seagate Barracuda 7200.14 XT for all my music and videos and files and bulky games. Theres no reason for an SSD when all you'll be accessing is music, videos, and files.