Well, you already know your budget and were you're buying it from so that leads you here.
My personal preference is Western Digital first, Seagate Second. Longer warranty on the Seagate though.
Things to consider:
Average Seek Time: = Lower the number, the better
Average Write Time: = Lower the number, the better
Cache: = Higher the number, the better.
Don't forget to include the $5.00 shipping in the price.
Have fun on that build.