Earlier this year I bought some seasons of Fringe on DVD. I'd never seen the show before, but I had read some good reviews. I wasn't disappointed as I started to watch season 1. If you're not familiar with the story, this is the summary from IMDb:
"The FBI teams up with a formerly-institutionalized scientist - who was performing experiments on the fringe of real science - and his son to investigate weird crimes that are seemingly part of a larger pattern, and may be connected with a global company called Massive Dynamic."
I have just this morning finished watching season 3, and as usual it ends on a cliffhanger that makes me want to start the next season asap. This show has great, quirky characters, which lend humour to much of the show, but it also has high drama, and of course sci-fi / action goodness to keep one hooked.
If you like sci-fi in a contemporary (most of the time) setting, I definitely recommend this show.