A new Logitech G105 Keyboard (MW3 edition) for $34.99 and free shipping from Newegg. Comes with adjustable green backlit keys, anti-ghosting, and macro keys. Personally, I don't feel the macro keys would come in handy when playing first-person shooter games, but they may help a lot in RPG games. See the page for more details.
As a side note, a can of spraypaint to cover the MW3 logo will cost just a couple of dollars from Amazon. ;)