I'm probably the youngest one in this thread right now lol, since I was born in '96.
but I'm definitely going with Cartoon Network, and luckily I was born just in time to catch the golden age of the channel before it ended in Summer 2004, since I was in Kindergarten through 2nd grade watching the network when they still used their original checkerboard logo that looks like this vvvv
and I was at the age of 5-8 watching the network regularly when they still used this logo from Summer 2001 through Spring 2004, I remember throughout the 1st half of my elementary school years coming home each Friday to watch new episodes of Samurai Jack, Justice League, Dexter's Lab, Johnny Bravo, Powerpuff Girls, Ed Edd n Eddy, Time Squad, Grim & Evil, Courage the Cowardly Dog, etc. Then during the weekends you had classic like the original Looney Tunes and Tom & Jerry, then you had movies shown during the weekends on Cartoon Theatre like Scooby-Doo on Zombie Island, Wakko's WIsh, Batman Beyond: Return of the Joker, and much more. My favorite year for Cartoon Network was 2002 in my opinion, that was the best, but the best year for Toonami was 2003 especially that summer though with Yu Yu Hakusho, Rurouni Kenshin, Dragon Ball Z, G Gundam, He-Man, and Justice League. Here's my best memories of the channel in its golden years.