7,200rpm HD on a M2 ? has anyone did it?

Am trying to Upgrade my old M2 (love it by the way, has been working steady for 3 years now) ... because it has been such a road warrior for me, I just bought 2gb of RAM (Crucial) ... and next I want to Upgrade my Hard Drive.
What is the Fastest and the Largest Hard Drive any of you have put into your M2 ( any M series Toshiba, might relate)
I here the 7,200rpm might run too hot in the M2 ... and also notice Toshiba does not offer it as a option (maybe for a reason)

Heat is my main concern / and that would also relate to Reliability ... and noise if all things are equel.

Right now I am thinking about the Seagate 100gb 7,200rpm or the Hitachi 100gb 7,200rpm ... because these are the largest 7,200rpm ATA 2.5" I can find right now ... If anyone knows of better one's please let me know.
p.s. what have you heard about the reliability of these 7,200rpm drives?

OR the Seagate 5400rpm 160mb is also a option. I do like the 5 yrs warrentee on the Seagates ( but in general like the Hitachi's better )

*** Please, post Links to the drive on a On-Line web store of the drive if possable.

* Right now I have a 5,400rpm 40mb that is silent and running cool and have has ZERO problems with it. Will be putting it in a USB enclosure when I swap it out.

Thank you all in advance for your Advice and Help ...
RDH