I put myself down for 3.
1) Craftworld Eldar: about 6000 or 7000pts, including a titan and a cobra super heavy. Probably about 2000pts of it painted

I bought em cos eldar, squats, orks and marines were the only models available at the time and my mate wanted squats and orks were never really my thing. I did get marines, though. Long time ago now, mind you...
Anyway - me's a lifer eldar player. The painting theme of the army is: slow
2) Plague Marines: about 3000pts of fully, gloriously pustulently painted plague marines. Death Guard, and every last one of em is converted in some way

Over and above this, a squad of 7 bikers, a lord on a palanquin, a sorceror, a greater daemon, and Typhus are all in the works. I got these guys as I see them as being different to my eldar in every way imaginable. The painting theme of the army is: variations on the colour green, and weathering.
3) Dark Eldar: my current work in progress I'm still buying/painting these chaps, but am aiming for about 3000pts. Hopefully they will be done by the Golden Week game. They were bought purely for the models (well, fluff, a bit. mwahahahaha, and whatnot) and the painting theme of the army is: improving my airbrush skills, and painting fast-but-tabletoply-nice.
Right now, however, all of the above are kinda on hold till I get some more Cryx painted, as Winter Blitz is getting worryingly close and all I have ready is one warcaster and a mechanical flea...