I think I would like psych from the previews I have seen. I watch Dexter on my own (a bit to morbid for the wife) and it is probably my favorite TV show. Of course, I never watch it on TV because I never watch TV. The combination of TV-on-DVD and netflix instant streaming on the Xbox is definitely handy if one is anti-tv.
I kind of want to check out Fringe and Dollhouse, too, the latter of which is created by the guy that did Firefly, plus Elisha Dushku or whatever her name is is a fox. For a while we were rotating through Burn Notice, Lie To Me, and Leverage, but some of the acting is pretty bad in Leverage and it tends to get silly at times, so we scratched that one. We have also never finished the second season of 24 because honestly, the every-episode-is-a-cliffhanger got pretty old. It will be nice to add a few new shows to the mix.