Just wondering how hot does a 7200rpm drive run before it gets too hot?

I have a 1 year old 6.4gb Quantum HD, and it runs at 7200rpm without getting noticeably hot when I touch it. However, my 2 year old 14.4gb IBM Desktar HD runs very hot, too hot to touch. Is this bad? The IBM came with my Dell and it didn't have any special cooling devices for the 2 years I used it (no problems during that time). But since I moved to a new place that's warmer, I've been a little worried. Recently, I moved the IBM HD to another drive bay with 3 small fans blowing cool air over it. Very inconvenient location though, as I need to use that drive bay real soon for another device. I would like to move the HD back to its original location, but am concerned by temps.