Seekers of Truth by Royal Cactus from the Bolter & Chainsword - You don't often see someone taking the loyalist Space Marine Terminators and converting them into Chaos Terminators. But this has really worked. The powerfist is just awesome.
Pandemonium Genesis Cultists by Kouzes le from Blog de Kouzes - A interesting approach to washing some cultists. I've never seen matt medium used before. So I'm not sure how unique this approach is... but it's something to consider given that I've got 35 of these guys to paint. There is also Games Workshops own Youtube tutorial.