i've just put XP pro on a friend's machine to replace Vista. I noticed the lack of fan noise, and installed Speedfan, and checked "Automatic fan speed". To make sure that it started with Windows, I used an all-in-one tuneup programme, to add it to the start list.
It still doesn't run cool, but 60-80 C is not very different from the vista figures...
of 60 - 80 C
HTH