Anime:
Cowboy Bebop - Just an unbeatable show. It's smart, picks off around the third episode and never ever looks back after that. Space genre mixed with absolute lunacy and some ground breaking music.
Animated TV:
Archer - For the lols. What a brilliant show. Laana, Laana, Laana, laaaaaaaaaaaaaaaaaaaana.
Futurama - This show has it's good moments, and bad moments, and then some out of the world moments that make you go woah, I was watching this for the laughs not crying inside my blanket. Rick and Moriarty, Bojack Horseman pale in front of the show with their fake deep intelligence that is the norm these days. This isn't an animated show pretending to be something more, it's just what it is. Dr. Zoidberg and Bender are unforgettable.
Cartoons:
The Adventures of Johny Quest & Swat Kats from the adventure genre. Johny Quest were ahead of their time, so much so that some of the three D rendering in the show really is an eye sore if you watch them now.
Voltron, Defenders of the universe (and the reboot too) - Mostly for the nostalgia but they had their good moments.
Honorable mention to South Park but I don't like the language used in it anymore. Ed Edd and Eddy were good too.