Fair enough. I think at most there are a few isolated cases of machines that run warmer than normal. The only real mentions I've seen were in the RAM upgrade thread, where a few people mentioned that their machines seemed warmer with a 2GB chip instead of the default 1GB chip (and that depends on the make of the chip). But those were just mentions of extra warmth (not 'burning hot' or anything), and I haven't seen anything about actual shutdowns or anything due to being too hot. So I'd say it isn't anything you should really worry about.