I still keep watching this show, repeating certain lines, and even collecting great fanart from this amazing show. It is about a teenage boy Danny Fenton who gains ghost powers in an accident and fights menacing ghosts becoming Danny Phantom. He often uses his parents' 'failed' or forgotten inventions and gadgets. Danny Phantom deals with unique situations, well written plots, and characters are likeable and that is something that the audience can relate to. Even most of the villains/antagonists are cool and well written. It has so much depth in it. It has great humor with great action. The humor is more situational and sophisticate but is a little corny at times but never too dark. On top of that, the characters develop. Despite dealing with ghosts, fear, and even in a few cases death; it's really not that dark of a show. (Although some episodes and scenes are darker than others, but still worth Danny Phantom is overall a show about dealing with hero work and everyday issues and troubles plus major possible life altering problems.
It is still way better than those disgusting, lousy, stupid, and repetitive shows that Nick replaced it with and continues to air to this day. As good as it is, not all episodes are the same in value. Some are better than others. It did started going downhill in season 3 when Butch Hartman the creator did some things that caused its quality to suffer. (Mainly he tried to make more like his earlier show Fairly Odd Parents which didn't use the same formula that made Danny Phantom a success. Hartman also forced off writer/fellow co-creator Steve Marmel who helped build up this show from the beginning and made the success it was recognized During that time, new management came in to power and cancelled it for other shows that paled in comparison. There was going to be so much for that this show could have done/covered.
In shorter words all I really can do is recommend this show whether you like super-heroes, action, sci-fi, fantasy, animation, ghosts, comedy, or any combination of the mentioned. Just about anyone of any age can like this show for a variety of reasons. I'm so saving this special show for my own children. All I can say now is "GOING GHOST!!!!"