They're not too bad now with more modern components, I've got an i7 laptop which could probably be considered a gaming laptop and it doesn't get anywhere near as hot as my old one did. I use a cooling pad anyway but that's more out of habit than necessity now, it never hurts to keep your system cool.
Gaming laptops usually cost a lot of money though. For example, I would expect an alienware laptop to be designed to vent excess heat because the components will obviously get hot and this forward thinking is reflected in the pricetag. My experience with your standard retail laptop though, is that it will overheat quickly and easily. And not many people realise the damage it can cause if it is in your lap most of the time.
I bought a MacBook Pro 5 years ago. Under a week after buying it, I dual-booted Windows.
I mainly see a lot of students using macbooks at my university, with absolutely no reason for paying an extra $1000 for a machine when all it's giving them over your standard run of the mill Dell/Acer/Toshiba/HP is a glowing apple. I have no issue with Mac OSX, for most non-gaming uses it's completely competitive with windows. The machines are just way more expensive than what the hardware inside offers.