Here are my top 5 (out of about 20!)
Project 1: Kelly and Kelly
Tidy up the greenstuff on the legs of the converted version and paint both. Base my Unity Council Predator Drone from Anvil Industries. What, you didn't think she was checking her facebook page did you?
Project 2: Dark Legion
Paint everything here. Phase 2 requires me to assemble and paint my Black Widow, Razides and Stalkers.
Project 3: 200 Point IG Kill Team
Inspired by Warren (from Beasts of War) and his rediscovered enthusiasm for 40k. Source - or possibly *gulp* sculpt - some arms. Buy a Taurox and the wheel kit from Victoria Miniatures. Paint it all.
Project 4: Star Wars minis
After messing up most of these with a bad undercoat, they are finally stripped and I am ready to start again. I need to scratch build a DC15A and maybe rebuild the DC15S to make it smaller, then paint them up.
Project 5: Pathfinder Tiles
Lots! Inspired by the Kingmaker adventure path for Pathfinder and the Mighty Empires tiles from GW, these were just an experiment and still need a little more highlighting, some holes drilled in them (for flags / markers) and some magnets on the back. Then I just need to make another ~300 more.
Definitely not cost effective, but fun to make!