My everyday rig is a Bose compact ... if I need more "ooomph", I have a 12" 150watt bass amp in the trunk for added bottom, but I almost never need it unless it's all kids, or I'm outside.
For larger rooms or more critical setup, I have a Mackie mixer, 2? QSC K8s, and the new EV 12" sub - this is the most efficient system I ever had, and it fits in my mid sized Ford Fusion. Nothing is too heavy to lug either!