What kind of cooling systems work the best? I've found cooling docks with their own fans, and ones that lift the laptop up using some kind of insulating material to protect your lap. The fan-based ones would seem to be the best choice, but I've also seen some claims that these can interfere with the laptop's own ventilation system. One website also claimed they can damage your USB port, but I don't know how much faith I'm willing to put into that comment.

This is the one I'm interested in at the moment. So what would you guys suggest? Are these really necessary? Are they even any good? I'm interested because I just had to put my laptop in for repair to get the fan replaced, and it has always seemed to run warm/hot after a while.

running warm wont hurt it... if it runs too hot you will know. It should not over heat with its oem cooling systems as long as you havent modified it.