Black Templars, Rogue Trader Howling Griffons, and Heresy-era Blood Drinkers/Angels, (plus Deathwing and Plague Marines too) to start another Space Marine army.
I have two Calth boxes and five MKIII suits for a command squad, so that should pretty much do me for Marines. I reckon 30-40 Tactical Squad Marines and 10 Iron Havocs with lascannons, and perhaps a 10-man Tac Support squad or even Assault Squad made with Forgeworld accessory goodies. Ten Cataphractii Terminators of course, done up as Siege Tyrants with added missile racks, likely from some third party vendor. There's two Contemptor Dreadnoughts in those boxes too, along with an Iron Warriors body on the way. I have some Praetors about that could go Iron, as well as a MKII Command set with banner and leader-type coming. Vehicle support will be sparse but powerful to start with anyway, as I've ordered up a Legion Medusa (hopefully a better kit than the Armageddon pattern vehicle) and the irresistible Typhon heavy siege tank for some serious line-breaking.
"Iron within, iron without!" :-)