I've had a Fujitsu Siemens laptop for a year and a half now and have suffered most days from hot legs, as it gets extremely hot after a few hours of use. It became too much so I thought I'd give this CushTop from Belkin a try. Simply put, it's an excellent product.
Pros+:
Very comfortable - raises laptop to a perfect angle and height for me (I use the 17" side for my 15.4" laptop)
Keeps legs nice and cool
Very sturdy
Gap in middle - stuff your mouse/power adaptor/TV Remote(!) in there (this also serves well as a handle to easily lift and put down the CushTop/laptop on the floor for example.
Semi-portable
Cleans easily
Stylish - available in different colour schemes - orange and steel was my favourite
Belkin Lifetime Warranty
Cons-:
Doesn't fold flat so I can see it being bulky in some situations (especially travel)
Sometimes the feet on your notebook sink into the material meaning the air vents on the bottom become blocked (not too much of an issue though I don't think)
Highly recommended, more pros that cons and well worth it.