<< they should be fine, i've got a 7200 and it's on alot, it'd sear my finger if i left it on there too long...WOAH...it's "normal" i did a slight case mod and put an 80mm fan above my hd bay to suck the air out, lowered my sys temp by 3 degrees. just put a fan on 'em, you can find really quiet fans, if the one from your power supply doesn't bug you, i'm sure you can find a quieter one, and every little bit helps. gl >>
A little tip from the tuna: Your intakes on the front should blow IN and on the back suck out. I have no idea of your entire setup, but the more you have blowing out the front, the more that will be pulled in the back. My 80 mil going over my 60GXP moves about 30CFM. That air is barely warmed at all, but the HD is so cool it feels room temperature. The little heat of the HD is not worth the mess of having front fans blowing out.