Two entries left and it's a no brainer, Top 10 Best Cartoon Network shows, done in two parts due to length as there is much to say. Lets get to it then.

10. Megas XLR
We start off the epic top ten with an epic mecha series, Megas XLR. It starts off as your typical sci-fi affair, the earth is fighting a losing war in the future and a woman named Kiva believes that sending MEGAS, a giant robot back in time before the losing battle, can tip the scales into the hands of the humans, however something goes wrong and it ends up in the 1930s inside a junkyard to then be discovered by main character Coop in the early 2000s, so what do you do with this giant discovery? Give it a paint job and replace the head with a muscle car, add in a few modifications and you've got yourself the most awesome mecha of all time until Gurren Lagann showed up, so you can almost call Megas XLR the influence or at least the foreshadow for Gurren Lagann.
What Megas XLR did for the mecha genre and for a cartoon series not an anime series to change the rules which had been so carefully woven into place by the likes of Gundam & further pushing the boundaries was of course Evangelion, but to put it into context, the likes of G Gundam nearly destroyed the genre in the 90s, mainly because the general consensus was that they grew out of what I call the Rocket Punch era of the 70s with the likes of Getter Robo & Mazinger Z.
The ironic twist in the tale was that G Gundam's over the top martial arts robot fighting anime was well understood by the American viewers, and Transformers wasn't ready yet for another remake so they turned to Cartoon Network for advice and they came up with Megas XLR, and suddenly we remembered that we could have fun with the mecha genre again. Rule breaking and game changing makes history and creates worthy successors and Megas XLR reminded Japan of what it's missing out on.

9. Dexter's Laboratory
During Genndy Tartakovsky's college years he submitted a number of shorts to Hanna Barbara's studios who were working with the Network to produce new home made cartoons, this would become Dexter's Laboratory, a show about a vertically challenged boy and his incredibly well designed lab; much of the series focuses on the constant conflict with his older sister Dee Dee who sees the lab as an extended playground. Creativity has always been the biggest strength with Dexter's Lab and it's always been supported by strong writing and well understood references such as the Justice League spoof, a James Bond-esque episode about retrieving camera film and lets not forget the Speed Racer spoof which also features the trademark fast talking.
Dexter as a character is full of pride and has a big ego, which makes up for his height issues, a number of episodes also explores him over coming such obstacles like the Dodgeball episode but at the same time can also be used against him when a potential solution becomes a problem such as Dexter's bad day when he ends up dropping the moon on himself or the episode where attempting to pass a French test ends up learning one phrase which he can't stop saying and although it earns him plenty of praise it also destroys his lab when he can't access the password lock to his lab. But it's not just Dexter & Dee Dee; Mom & Dad also have their moments, particularly when Mom gained Superpowers or being on the receiving end of a Tom & Jerry reference but the comedy king has to be Dad when he's either trying to eat muffins or throwing snowballs, every scene he's in is pure gold. I will admit that when Genndy left the show and another series came out it lost it's charm and traded some of it's comedy for backstory which wasn't the best route to take and the series ended silently. But Dexter's Lab holds an important legacy for the Network and remains the finest cartoon of the 90s.

8. Hero 108
Here's how a political cartoon for kids should work; animals live in harmony with humans until a man named High Roller tricked the animals into thinking the humans are enemies, until an army of heroes led by commander Apetrully (Who is the Monkey King) attempts to stop the conflict through any means necessary but as it's a kids show most battles end in a special contest that tests more than just strength and this is where the show wins. Considering that Lin Chung on a good day can battle entire armies on his own, the episodes do their best to balance out the qualities of the other main characters and even the villains can be seen as very capable in the right situation, it's also clear that the heroes don't win every time either with the likes of the Eagles & Chameleons still refusing to join despite more than one episode screen time, even characters who changed sides before continue to have doubts and have to be defeated all over again, and that's what this series does, it keeps surprising people with it's content, for instance the DoReMi band plays mostly traditional Oriental music until a fight with the Frog Kingdom ends in them playing heavy metal music, you don't expect that in a series that keeps a lot of it's grass roots in oriental culture alive. A free fact for you, this series is loosely based on a Chinese Novel called the Water Margin in which the main character is also called Lin Chung, an interesting thing to keep in mind as I would like to see them attempt Romance of the Three Kingdoms next.

7. The Amazing World of Gumball
While in college, creator Ben Bocquelet decided to make a series out of his advertisement character projects, but what's interesting to bare in mind is that a number of his creations utilized different animation styles such as traditional 2D, Stop Motion, CGI, Live Action photography and even Muppets. But as Pixar will tell you the real glory of a cartoon comes from it's writing and Gumball has some of the finest "British" comedy writers working on the show. It features title character Gumball Watterson, a blue cat in a dysfunctional family with a workaholic mom, a lazy dad, a genius little sister and an adopted brother in former pet fish Darwin. For as long as I can remember most young child characters are voiced by women; in this show, Gumball, Darwin & Anais are all voiced by children of the right age giving their reactions to the many situations around them a more authentic feel.
To give another example, Boo of Monsters Inc is also voiced by a child of the right age. But again it's the writing that sells the show, such as drawing a criminal as a talking fingerprint or riding a mop bucket down the highways to avoid bad luck or the Street Fighter II spoof which looks more awesome played to Guile's theme. British and proud, Amazing World of Gumball will stand the tests of time.

6. Ed, Edd & Eddy
Hands up if you know someone who acts like a character from this show? I'm going to guess that at least 90% of people reading this are going to raise their hands. Ed, Edd & Eddy features a group of friends trying to create schemes to make money and buy sweets, basically a normal day in Suburban America and it's something which is understood by everyone who's seen this show as they may have been the same when they were younger. Originally creator Danny Antonucci did adult cartoons and someone dared him to do a children's cartoon, so he conceived Ed, Edd & Eddy while working on advertisement (If you ever choose a career path as a cartoonist you must work in advertisement and marketing as a support) he liked the ideas he drew and sent the pilot episode to both Cartoon Network & Nickelodeon but both channels wanted creative control which the creator didn't like, Cartoon Network eventually agreed to the terms and Ed, Edd & Eddy became the longest running show on Cartoon Network, not to mention one of the longest running Canadian shows being Canadian made. Keeping creative control allowed Antonucci to really connect to the psyche of kids growing up in suburbia, even though I'm British it still connects with my inner child. I was friends with the crazy foreigner, I knew many people who were the bad boy bully, I've met a number of girls who are trailer trash, I went to school with an Eddy, in fact I'm Double D with the geeky mindset of Ed. All that from a cartoon made from a dare and the creator even had creative control which very rarely happens in cartoons of that era. Nickelodeon will forever kick themselves for letting that one go.
It does still baffle me that Kira Yamato of Gundam Seed is Ed, and that Athrun Zala of the same series is Double D.