My vote goes to old 5D. It can be had for very reasonable price and image quality is still top notch. I do also believe that FF EVIL camera will be coming pretty soon, so I can't justify paying big $$$ for 5DmkII (but I'm not a pro)
I use 5D with MF lenses only.
4/3 with 12-60mm and Lux 25mm (I believe there isn't many AF lenses in any system that can beat this combo)
And m4/3 again mainly with MF lenses, plus 7-14 and 20mm.
I love them all, but I think if I had to choose one system only, I'd go with m4/3, for its size/performance ratio, cine lens compatibility and EVF of ep-2.