The only chapter I could ever do would be the Fists. I love the fluff, their Primarch, the color scheme, everything.
I picked up a Tac Squad earlier this week and used the last day of my vaca to put them together. My idea for this army is a veteran force of hardcore city fighters. Since your typical Marine mini is a tad boring, I decided to pay more attention to their bases. I'm using plasticard to replicate steel flooring (which I need to clean up the edges of) and plan on using pieces of rubble and destroyed walls freely as well. I also want to make them look like they've been in constant war for a while; pieces of their armor are blasted and in desperate need or repair.
Stay tuned, more yellow is on the way!