Yeah the Wii doesn't overheat like some other systems do -cough- xbox360 -cough- :smilewinkgrin: . Just as long you don't block the fans and vents, you'll be fine.
I wouldn't get one because I bough a air thing and all it is is loud and annoying it didn't help me at all so now I never use it. I guess if you leave your Wii on for like three days non stop there is a chance you might need one but other than that they are a waste of money.
i got a fan exhaust that goes behind the wii where the usb port is, its loud and i duno if it does anything but i leave my wii24 on all day and its juss warm its just ur opinion really.
i got a wii fan stand from gamestop because i have it enclosed with a glass cabinet door and it keeps it cooled down or else it would get hot in there and it looks pretty snazzy with the blue light and all