The only problem I see with the Canon setup is that it uses an infrared transmitter / receiver. This works the same as your TV remote, only on steroids. It isn't dependant on line of site, infrared bounces around pretty good actually, but it can be blocked.
Another option that is just about as expensive is to buy some Pocket Wizards. They make a reciever that is designed to trip the shutter on cameras, a coworker has one for his 1D MII. I'm not sure the total cost, but can't imagine it being any more than the Canon kit, probably not much less. There are a few big advantages to getting the Pocket Wizards. One is that they are mutli-channel, designed to trigger flashes, so you can shoot with studio strobes wirelessly. Second is (as mentioned above) that you can get a reciever for your camera, to trip the shutter. And the really big one, these are real, radio transmitters that will go through things, don't depend on line of site, and are very reliable indoors and especially outdoors.
So if you are really going to spend the money, get the Pocket Wizards. They will do a lot more for you for probably close to the same price, depending on how many recievers you buy.