Heh, HHD is a Hybrid Hard Drive, which is a crossover between a traditional Mechanical HD, and a SSD. You might want a mod to change that title.
Check if your motherboard is SATA 6 gb/s compatible. Revision 3. Sata 6 HDs will work fine on Sata 3 MoBos, but there will be performance/speed loss.
And if you want two of that 1st WD drive, WD make one that's pretty much exactly the same, except 2TB: Newegg.com - Western Digital Caviar Black WD2002FAEX 2TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive
I would recommend the one I just linked, as it's got good reviews except people saying 'OMG DOA GAY 1 STAR' Which in my opinion, isn't based on the actual Hard Drive, just saying I don't care about performance, it's DOA so i give it 1 star >.>
I've just ordered it, and it should arrive within a month or two.