I got the Vantec laptop cooler a while ago (in fact, I believe my little mini-review is the first one posted on Newegg for that product) and it's definitely worth the money. It doesn't work all that great if you have the laptop on your lap alot, but on a table or some other flat surface it works great.
I got it for my wife's laptop because I commandeered (sp?) it to run a distributed computing program on it whenever she wasn't using it. With the CPU running at 100% (mobile Athlon 1500+ 1.3ghz), it definitely got too hot to put anywhere on your lap, and even the keyboard got pretty toasty. I was worried about the heat reducing the life of the laptop, so I got the Vantec. With the Vantec's fans going, though, the keyboard is now barely warm and I don't worry about shortening the laptop's life.
What sealed the deal for the Vantec (for me, at least) was that it adds 4 USB 2.0 ports, and it has it's own A/C power supply. Alot of coolers I looked at were powered thru one of the laptops USB ports (without adding any), and if you only have two USB ports to begin with, then you are really limiting what you can plug into the laptop.
My 2 cents.