Just bumping the thread. In answer to the question above the Gameservers Directly funds one L4D1 and one L4D2 server at the moment. I'm cancelling my Alien Assault servers as they don't really get enough use anyway, however if there is enough interest in starting up a COD:BO server (and I decide to get the game in the end) then obviously the donations will go towards that as well.
Obviously by relieving financial strain from me on these servers it means I can run the other servers I run more easily. If you want to fund the CSS and other L4D1+2 servers directly, then let me know and I'll send you the paypal details.