Circulating it in the cabinet works for me. I have a very minimal problem with the beer line in the tower perhaps being too warm. I suppose flex tubing air to it would cure it, but it isn't that bad. I'm still thinking that one day I will use the wimpy Danby fan tocool the tower that tad extra bit by moving it to the tower base or something.
I dunno. Right now I'm doing pretty good as far as cold beer goes. My next modification may be a two tap tower and two 1/4 barrels. Or I may just build a fullsize fridge kegerator and go whole hog. These two setups are way cool too:
http://www.west-point.org/users/usma.../kegerator.htm and
http://www.anthonyro.com/bar/
http://forums.the-hole.net/