7200rpm drives back when the PS3 came out were a completely different animal than drives today.
The 7200rpm WD Scorpio Black generates 1W more power than the 5400rpm WD Scorpio Blue, and the temperature difference is negligible between the two drives.
The stigma of "7200rpm drives will overheat my PS3" is pretty much a dead issue these days.
I've had a 750GB WB Scorpio Black in my CECH-3001 Slim PS3 for almost 8 months and I've not seen any issues with heat. I have seen quicker access on loading games and other disc-based work on the system.
The Scorpio Black is pretty much top of the heap for 7200rpm 2.5" HDDs, so it should be a difference between that drive and other drives, especially 5400rpm drives.
I own numerous Black drives (4 in a HTPC, 2 750GB and 2 500GB), 1 in a laptop at home (750GB), 1 in my PS3 (750GB) and two 320GB drives as external drives. Some are as old as 3 years and they've all worked fantastic. I also have a couple Blue drives and they all continue to work without issue.
If you're worried about head, get a Scorpio Blue. If you'd like a little more speed (and it's not night and day, though I think it's noticeable), get a Scorpio Black.