As an Englishman, I feel eminently qualified to discuss this subject.
Doctor Who is one of my favourite TV programs of all time. TV critic Charlie Brooker once remarked that every time he watched that series, he turned into an 8 year old boy. This I can understand. I know that there are better written shows out there, better acted, directed, and produced. Yet it does not matter one bit. Doctor Who has this magical sense of otherness that somehow enables the casual viewer to switch off each and every one of their critical faculties and just become transfixed for 40 minutes. Or in other words, become an 8-year old boy.
Monty Python's Flying Circus on the other hand I have found very hit and miss. For me, that is the problem with sketch shows. For ever Dead Parrot, Spam, or Buying and Argument moment, there are many more, far more forgettable incidents that time has somehow allowed us to gloss over. Yes, there are other great sketches, The Lumberjack song, The Spanish Inquisition (which you were expecting at some point), The Philosophy Football World Cup Final, etc. As sketch shows go, Monty Python is undoubtedly superb, I just am not much of a fan of sketch shows.
Other shows that deserve a mention:-
I, Claudius (1976) Drama mini-series that chronicles the lives and exploits of the early Caesars. This invents the 'history with the nasty bits left in sub genre' and yet, 35 years down the line, still seems to pull it off better than anyone else. Most probably because it had a superb script and a magnificent cast.
Tinker, Tailor, Soldier, Spy (1979) Spy Drama starring Alec Guinness. Some of you might remember that man looking very bored in Star Wars. He was one of the greatest actors that Britain ever produced. If you want to know how good he was, watch this. The finest single small screen performance ever given. You might also remember that Gary Oldman recently had a crack at the same recently as well.
Yes Minister (1980-84) Peerless political satire about a vain, bumbling, but good natured Politician, and his too clever by half private secretary. Americans might find this a little TOO British.
Blackadder (1983-89) Time-jumping sitcom that is only a little less quotable than Monty Python
House of Cards (1990) The original. Ian Richardson at his best, making Tywin Lannister seem almost amateurish by comparison.