What is a dual processor hard drive?

It has 2 processors on the circuit board, often one dedicated to servo tasks and one dedicated to IO and other tasks. I'd be surprised if you could notice the difference, though theoretically it's a bit faster.

So, it wouldn't be worth the additional $30? Would it be comparable to a 10,000rpm drive, or is that going too far?

For some tasks the wd 1tb black out preforms the raptor 10,000rpm drives.. now my dad has 4 10,000rpm velocraptor drives 300gigs in raid 0+1 and Ill admit its fast as heck but He also did 1tb black drives in raid 0 2 drives and I cant see a diffrence at all and for the price go 2 1tb and 1 ssd if you want really fast.. or you can do what this company did..

http://www.youtube.com/watch?v=96dWOEa4Djs

21 ssd drives man thats fast.... I got to get me one of thoses