I'm towards the end of Season 4 of Dexter. John Lithgow is an amazing antagonist in Season 4. The gf and I just finished Season 5 of Weeds. We laughed a ton.
Other series of honorable mention IMO are Flight of the Conchords, Summer Heights High, and I can't believe I didn't mention this before, but Skins (a BBC show) was probably one of the most interesting shows I've seen in a long time.