Well it all depends on your cooler and the usage. For gaming I would rather have a pc, just because if your video card is outdated you can upgrade, which isn't possible with most laptops.
Don't you mean desktops? Because laptops are PCs. I like laptops because I can take them most places with me without any hassle and I can access the Internet easily. The only problem I currently have with my laptop is the battery life - it only lasts about an hour before needing to be charged, but I plan on getting a better battery or even laptop soon because this one is two years old. Desktops are overall good if all you want is a nice computer to keep at home, and laptops so you can travel with it, so getting both is a good idea.
My desktop runs faster than my laptop, but I can't bring it anywhere. I like my desktop for games, due to the really big screen. But like Ghost said, both would be good to have if you use the internet a lot. (On my desktop right now :])
and if you want to bring your data along. then you only need to buy a external HDD of 1TB or something. then you can bring your data along and plug it in a other computer. 9 out of 10 times there are computers available somewhere.
having multiple custom built laptops and pc's i can honestly say i perfer the laptop because its portable, but performance wise, im sure no one will argue a desktop is much better. always get windows or linux.. mac is only good for video/picture editing.
Desktop are cheap and easily upgradable. If you are a 100% gamer you will have a desktop (or multiple desktop) in your place. But, if you need to work with your PC a laptop could be better, you can bring it anywhere you need it. Also, now there are some real good laptop that are able to run almost any game with full graphics. If you live in a small apartment and dont have the place for a desk, your solution is a laptop so when you can use your kitchen table. Again, if you have friends and like to LAN with them with some beers and etc. a laptop is good idea.
If you want to play new and "high-tech" video games, I would suggest to play on a PC
If you'r not at home that often or are very busy, I would prefere a Laptop. I'm using my laptop more often than my PC becuase it has better processor and graphic card. But even if i play L.A. Noire, Mafia 2 or GTA IV the performance will be higher on the laptop because of the "bad" cooling system.
that is so wrong alienware and other gaming pc brands make high power gaming laptopts. but then if u get a cheap netbook whaddya expect? it all depends