Laptop Cooling Fan

Does anyone know of or used any good laptop cooling fans? I want one top of the line, but I don't know what top of the line is.

I think the phrase "you get what you pay for" comes in to play here. The main thing is to get one that is about the same size as your laptop (don't buy one made for a netbook to use with a 19" laptop or vise versa), and if you can, read reviews online of the fan you buy before doing so. 90% of people aren't going to write a review on an item unless they have problems with it. If the reviews are all good, then you know its a good product.