full install, the main OS
Live USB Persistence
Dual boot with Windows.
Just jumped to live usb after running full install for quite awhile.
I use kali 1.1.0 on a live usb to carry around, and I run kali 2.0 as the main OS on my laptop.
I use a Live USB persistense, since it allows me to bring it everywhere easily.
Full Install on Laptop,VM on main Desktop PCLive USB for working place, vacation, Internet café etc.