Hi,
My TR3 originally came with a MK4004GAH. Each new generation of toshiba drives seem to run cooler than the previous ones. I had the MK4004GAH and a 8mm 20GB version from 2G ipod both in external cases awhile ago, and 20GB unit ran sigificantly hotter than the 40GB.
The MK6006GAH which I replaced the 4004 with ran noticeably cooler again, and I would assume with the non-zif 80gb unit would be better still. If you have a look at the spec sheets for each drive, the power usage will give you an idea of heat generation.
Currently I’m running an Samsung MCBOE32G8APR, which being solid state generates pretty much no heat at all. Though this isn’t a very cost effective option, as SSD’s are still rather expensive—however I use the machine for business and the speed increase justified the cost.
The 60GB unit does also have slightly higher transfer rates, so this might be a good option if you want cooler without spending too much money.
Matt.