Airport Card in MacBook Pro
If you have a non-Core-Duo MacBook Pro and would like WiFi N support, the Airport card in the AppleTV fits perfectly in the MacBook Pro.
I'm seeing reception improvements as well, but haven't tested the N capabilities yet.
Note: The Airport card from the MacBook Pro does fit into the AppleTV, but will need some kext patching. Assume that you will be losing WiFi capability if you do this swap. For me, this wasn't a problem, as I am using Ethernet for my AppleTV.