Laptops are a reasonable alternative to power/heat but you need to buy gaming laptops - not regular ones with shared video memory.

WoW needs 1 gig of dedicated memory, an actual video card of some kind and reasonably fast hard drive access (which laptops are a little slower in general on). Plus, you COULD mount the laptops but you would likely still need external displays.

No laptop can do dual link DVI and are limited in their ability to be upgraded. Plus, cooling is more difficult for when CPU load and GPU load peaks and stays peaked.

But the advantages are there- much less power use and a compact size. They might be a reasonable option for those who are looking to avoid the massive power use and heat problems associated with desktops.

Plus, they have built in UPSes Well kinda