Best levelmaker: Blackraptor. That guy puts so much needless work into everything it's amazing.
Best levelmaking group: Probably OLC... it's the only one that's particularly active, although one could assert that FSP was a CLM product. Whatever. OLC.

Best levelpack: I'm just going to have to go with FSP here. If I'm not allowed to, probably "Fearofdark: Jazz 1 Game".

Best tileset maker: Toxic Bunny.
Best tileset: hard to decide... let's just go with Windstorm Fortress.
Best JJ1 conversion: Exoticus.
Best JJ2 conversion: Are there any contenders for this other than Diamondus B, or am I just not understanding the question?