I have to say, the best comedy on tv right now is ABC's Modern Family. Most people agree, as it has won non-stop Emmy's since it's debut and has gained a large fanbase. Season 4 started up a few weeks ago and it just amazes me how good the writing is, week in and week out, on the show. I recommend checking out seasons 1 through 3 on DVD and then start watching Season 4 as each season and each episode is great. I really was not interested when it first came out a few years ago, but my sister got me into it and I am glad she did.
I am also a fan of The Office and Parks and Recreation on NBC, but The Office has gotten a little stale lately. Parks and Rec is still great, right behind Modern Family.
Check them out!