In the thick of it, HIMYM, the IT Crowd and the classics ie. black books and blackadder.
All Blackadder And Fawlty Towers :d
I enjoyed watching friends but I honestly can't say it made me laugh the most.
Friends was ****.
Red Dwarf, The League of Gentlemen, Only Fools & Horses, Cheers, Frasier, The Simpsons, South Park and (a guilty pleasure of mine) American Dad.
and my personal favourites, the absolutely outstanding Arrested Development (almost perfect as far as comedies go) and the brilliant Extras (better than The Office!)
I've yet to see Curb Your Enthusiasm, Seinfield or 30 Rock but I'd like to.
Only Friends, Only Fools and Horses and Fawlty Towers will make me laugh out loud.