HiJoshua
I've Got It
If you want a HD that works both on Mac & Windows bud then you'r limiting yourself already. As there are only 2 HDs released from a decent/well-known brand (Western Digital)
But if you wanted a HD for each PCs; Mac & Windows then it can be done. You should be able to get 2 decent HDs bud.
What do you want to do?
TheFNetwork
Hmm, well considering I go back and forth between uni and home a lot, and uni is all macs and I have all microsoft at home, I'd be interested to know what the two hard drives from WD are?

No harm in creating an extra backup I'm sure
. I have numerous backups as I have many HDs mainly External but one is Internal but it's connected to a docking station which has a "schedule" backup plan. I've never used dropbox as it will take only few seconds for me to fill the storage for a "free" user. One 720p video is just over 4gb's lols.