OK, a bit more to report. Today it was used in my office sporadically and it was reasonably warm (28 degrees C outside and prob about 19 in my office).
Fans have not come on as much, so I'm starting to think the drive is settling in.
CPU temps are higher than they were with the old drive, to be sure, but not high enough to trigger any more than 1800rpm from the fans. At 1800rpm, I don't hear it. Because the temps are higher, though, it takes less activity to put the CPUs up to where the fans crank up.
Right now: Firefox, NetNewsWire, Mail, Skype, PathFinder and iCal running. Temp is 53C, HDD is 33C. It's about 17 degrees in the room. Dunno, maybe that's not bad.