At the severe risk of being labeled a bandwagoner, I'm going to build a
Right now, I leaning towards White Scars: I have 9 SW bikes that sit in their foam tray alone and forsaken. Aesthetically, the WS are a good match with the SW, both have the barbarian look, both look great with some Marauder horsemen heads. Plus it's fluffy -- Leman Russ and Jaghatai Khan were pals -- Space Barbarians FTW!
It will be interesting to see what the rumored White Scars supplement adds to the mix, also it will be interesting to see how the supplement works with the main codex with respect to alliance with the main C:SM.
I'm considering the following:
Kosarroh Khan on Moondraken -- fun conversion opportunities here and fun rules.
4 Bikers with 2 Grav-guns and an Attack Bike with Mult-melta (troops)
Storm Talon with Sky-Hammer missiles.
Lot's of folks are building lists that go crazy with the grav-guns, largely in reaction to the plague of MC's that seemed to infest the 40k universe over the past couple of months. I think a more balanced approach will win out over time. I do like the synergy that will result from a alliance of SW and WS -- grav-guns are concussive; anything that takes a wound from but survives a grav-gun fusilade will be JOTW-bait.