Best JCS'er: N/a
While I have seen a bunch of 2008's levels, I don't think I've seen enough of some of the work of these people to fully appreciate their skills.

Best CTF/battle/other: N/a
I also don't think I've had enough experience in these category to really answer.

Best Multiplayer Pack: Memories 2
The normal levels Hitch made were pretty high quality, and the bonus flag run level was awesome. I love the dead-zone concept.

Best Single Player: O Brother
Maybe this didn't have any groundbreaking new gameplay or anything, but the ending gave it the cooles plot I've seen in an upload on J2O.

Best Tileset: Gothic Cathederal
This is a very beautiful tileset. I especially love the roman numeral destruct scenery tiles. Only thing that I don't like about it is that it is too big for 1.23

Most Improved: N/a
I haven't been around long enough. I don't know what anyone's old work looks like.