I wouldn't say the humour has dated really, it's certainly worn a lot better than other comedies of the 70s. If you were going to aim a criticism at the TV show it would be that it could be somewhat hit and miss at times. But dated? I don't agree.
"Excuse me Miss, do you like pineapple?"
I think Monty Python is unfunny in some parts. Though it's not overrated, as it was totally different to comedy at the time, and I have yet to see much that can rival it in terms of comedic genius. They're the Beatles of comedy, really.
Also, they're vastly funnier than most modern comedy. My god, the new stuff all sucks. ENOUGH OF THE LAME SITCOMS. I just want to see some random, funny sketches, or more decent sitcoms.
Bring on Morecambe and Wise reruns! Bring on Red Dwarf! Bring on Faulty Towers, and all the other classics! I would be quite happy if they just repeated the IT Crowd, rather than introduce new *cough crap cough* "comedy" programmes.