What files do I need to remove to wipe every trace of iTunes from my Mac filesystem?
The ones I know of are:

~/Library/iTunes/

/Library/iTunes/

~/Library/Application Support/MobileSync

~/Library/Preferences/com.apple.iTunes.plist + more similar .plist files

However there are probably a LOT more hidden throughout the OS. As soulshined pointed out there are parts of the OS that depend on having iTunes, and removing it would break them. I am curious as to why you need to?