Here are my nominations:

LincolnPirate ... most mysterious (has anyone actually met this f*cker?)
Darude ... most pro-social outing.
T com ... wisest (he told me early on, 'ignore everyone you meet on QL'. He was right).
Segmund ... most intolerant.
Molten Metal ... most difficult to understand grammatically.
Britexpat ... most unfunnny.
Screaming Bee ... most likely to post something she doesn't mean.
Dracula ... most laid back.