I've been watching a LOT of TV. 
NCIS, Bones, The Wire, Rome, Dexter, Mad Men, BSG are all pretty good shows. Some are more intense, others are more casual watch and sit back. 
The Wire, and Mad Men are shows where I think you need to give it several episodes before you get a feel for the show. The pilot's aren't "catch you and grab you" but more "we're setting stuff up and you'll see why". IMO in both cases it is worth it. Rome the first episode was ZZZZZ but the second episode on really picks up. 
NCIS and Bones I watch mainly for the team interactions, not the crime component (though the crime component is sometimes interesting). I like NCIS more than Bones, but both have been a good way to kill time by watching an episode. Though once you watch enough of each show the episodes fall into pretty predictable formats.
If you haven't already seen them or if it's been awhile : Star Trek Deep Space 9 and Babylon 5 are probably worth a watch. I like DS9 better myself (Gasp, I'm sorry) but B5 is definitely one of the greatest scifi shows. Stargate SG-1 I hear is good and a friend had the box set so I'm going through those now... as soon as I'm done with the wire 
 
I also enjoyed Spooks (from the BBC). It was slow at first and the sound values seem off (hard to hear characters sometime) but I really started to like it around season 2.