Now i know i'm not the only who's made this connection (in fact, i've brought this up at a few other places on the internet), so i'm bringing it up here.
As anybody who's watched both shows would know both show combine the martial arts genre with the four traditional elements: Water, Fire, Earth and Air (or Wind in Xiaolin Showdown's case). However, there's point in trying to deny it, Avatar is clearly the better show. It has real serious tones, gives real dimmension to the characters and the animation and Martial Art moves are all just done beautifully.
Still though, one thing i have to give Xiaolin Showdown is that because of its ambiguous tendencies, it leaves a lot for the fans to imagine for themselves. And for budding writers, that just paves the way for any number of fan fiction ideas.
Avatar, on the other hand, is different. The show may occasionally leave a few plot-holes open, but sooner or later those question get answered in full, be it by the creators themselves, through episode commentary or even within the series itself. To put it simply, Mike and Bryan are apparently making sure that no question gets left unanswered in this franchise. Not saying that's a bad thing, but it doesn't leave much to the imagination either.
What about you, what you think