This may be a tad premature as my nominee hasn't been with us for two months yet (though he's been pretty prolific in that time), but I wouldn't get the chance next year, so I'm going to go with
net2007.

He's knowledgeable, unpredictable, prepared to back up his arguments pretty forcefully - and he does his research. He can be a tad snarky at times, but is otherwise shaping up to be reasonably formidable.