Fyi: I recently ordered 3 different type/sizes of cheap rip-offs of the new Canon caps (complete with Canon print :-)) from China/HK, and ...
* In one type, the clip system isn't very smooth so it doesn't really snap but I have to push the clips outwards (though I might find some way to grease them :-p)
* In another type the Canon print only consists of type stickers that instantly fell off :->
* Another type is really good, though it's nearly impossible to tell one type from the other: http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=271151175422
Still, if you have time enough to wait for the delivery it's worth trying a few since they are so cheap, and it's much easier using these with the lens hood on than the older Canon system with the clips on the outside.