I recently bought a Hauppauge WinTV-HVR 950Q Hybrid TV USB Stick for my laptop -- for less than the cost of a portable digital TV. This model works on both Macs and Windows (check the computer system requirements before purchasing); plus it comes with a little antenna that's not too bad in a pinch. You can pick up a better set of rabbit ears just about anywhere for 7 bucks.

My laptop most certainly requires more battery power than a little portable digital TV but, now that my B&W battery powered analog TV is obsolete, I didn't want to acquire yet another gizmo (requiring special batteries, no doubt).

Scott
New Orleans