If you are concerned about how something looks on an HDTV, in HDTV color space (ie Rec 709), then using the built in graphics card on your computer is not sufficiently accurate. You can mimic a broadcast signal on a consumer set, but your calibration options are limited. Does your MacBook Pro have Thunderbolt? Then some of the newer Black Magic and Matrox options can be driven via TB. If your MacBook has a PCIExpress slot, then you can do the same with a card adapter. If you have neither and just have FW or USB, then you can't really do that. It is still possible to use your graphics card via a Matrox MXO (not MXO2) box which can drive a monitor using your DVI or displayport out.
As far as Flash Drives on TVs, not sure what you mean: connecting the flash drive directly to the TV? I thought we're talking about playing FCP etc from your laptop....