Minotaurs: Secretive chapter descended from an unknown founding chapter. Express general disdain for imperial authority but curiously enough respond immediately to orders from the High Lords of Terra. Forced the Lamenters to surrender during the Badab War Novamarines: Descendants of the Ultramarines. Known for providing rapid response by coming to the aid of any Space Marine chapter who requests it. They wear a cool looking quartered blue and bone colored armor. Mantis Warriors: Sided with rebels during the Badab war but were granted the Emperor’s forgiveness and sent on a 100 year crusade. A White Scars founded chapter. Death Spectres: Founded by the Raven Guard, they must experience death and escape it’s grasp multiple times in order to become fully fledged Space Marines. Their Chapter Master is bound to something that is apparently similar to the Emperors Golden Throne, where his life force is sacrificed for some unknown purpose. Exorcists: Demon hunting specialists who are supposedly founded by the Grey Knights. Each Marine gets possessed by a warp demon for a short period of time to make them more effective demon killers. Also, according to the Deathwatch novel, they have no soul.
Exorcists well cause killing demons is a hobby of mine (Doom series)(granted their Aliens who look like demons...but who care ^_^)
Out the choices, I like the Novamarines the most. However, if we get to roam around and explore the fortress monastery of our respective chapters (which if possible would hopefully be unique to each chapter, instead of a generic space marine model with different colors) then my choice would be the Red Scorpions, I would love to explore the Vigil and train there given the chance.
Out of these I'd definitely go Exorcists. They're like Grey Knights, but with less Inquisition control.