I meant to answer this a week or so ago. Tyler Labine, the drunk Steeler fan, has not been in anything great but has been the best thing in a number of shows he has been in. I thought he was the best part of "Invasion" from a couple of years ago, and he is in "Reaper" right now and close to the best thing in it, the 4th I guess. Ray Wise is the best by far, then second and third place go to Missy Peregrym, then 4th best is Labine.
Speaking of good things in not so great shows, Kyle Bornheimer is fantastic in the very average but watchable "Worst Week". He reminds me of John Ritter during the good years of Threes Company.
And "Chuck" is on of the silliest but enjoyable hours on TV.