I watch the TV shows I download from iTunes on my laptop. I don't think it's worth getting an iPod just to watch iTunes stuff on your TV. You've got to buy a dock with cables. And, after downloading the movie, you've got to sync your iPod, then move it over to the dock by the TV, then start fiddling around with the TV input setting and navigating your iPod. Bleh!
Until iTV comes out, which will streamline this process (if it's designed well it will, anyway), get your shows from somewhere else, or watch them on your computer (this is really not as bad as it sounds, once you get used to it.)
...unless you just want an excuse to get an iPod, that is 😉 In that case, go for it 😀