Second the recommendation for Coupling - it’s an excellently written sitcom, and if you liked Fawlty Towers, you’ll probably like it. Not that it’s particularly similar, but it has brilliant awkward moments, great dialogue and situations and engaging characters.
Spaced is another sitcom, from the same stable as Shaun of the Dead and Hot Fuzz.
The Mighty Boosh is good, but if you didn’t like Monty Python, you might not like it, as it’s a bit surreal.
“Doc Martin” – Aspergersesque surgeon develops a fear of blood, so he becomes a GP in a tiny Cornish village. Quirky character-driven comedy. I romped through all four seasons available so far very quickly – the fifth season is supposed to start airing in the UK soon, I hope it comes to the US soon after.