I think you'd be better off with a 7200rpm to be honest.
Some of the benchmarks say that a 7200rpm vs a 5400rpm actually has a noticable difference, but anything above that seems to be limited by the PS3's SATA1.5.
I'm using a 500GB Seagate Momentus 7200rpm in my fatty PS3, no heat problems at all!
60GB (120GB WD Scorpio Drive) PS3 (CECHA01, NTSC), 3.7OFW
60GB (640GB Samsung Drive) PS3 (CECHC04, PAL), Kmeaw 3.55, Repaired (Dead Laser)
PSP-1003 FAT, CFW5.00 M33-6 & Prometheus v2
X-Box 360 Xenon (JTAG'ed, 500GB HDD)