Funny thing about the Charlie Brown and Snoopy Show... Ol' Sparky was reluctant to give them a Saturday morning cartoon series for the longest time. It wasn't until the early 80's when he finally broke down. And since they were based mostly from the comics, you know they were good.
Of course, the idea to keep making TV specials posthumously following the same guide lines gave us enjoyable, but ultimately forgettable, results. Especially since "I want a Puppy for Christmas, Charlie Brown" features a sequence that was also used in the CB+SS episode "Spike." Of course, "Spike" got its point accross in less than 5 minutes.
Anyway, the bigger success was the Garfield and Friends series. This is probably the first variety comic strip show featuring 2 comics, both by the same creator... Other "variety" comic shows featured different strips by different creators... Fabulous Funnies, for example, featured stuff like Alley Opp, Katzenjammer Kids, and Broomhilda. Heathcliff had 3 different cartoon shows, but he shared it with 2 non-comic strip entries (Dingbat and under DIC productions, the Catillac cats) and one from the comics (Marmaduke). I have only seen Dic's version.