Nah, Gaara is too over rated. He's one of my favorite characters, but he's built up too much and loses. Naruto, Kimimaru, and Deidara have all beaten him. Kimimaru would've killed him but he died just in time to save Gaara, so I guess that's a win for Gaara. He loses too much, yet he's Kazekage.
Goku would win simply because he's the strongest in DBZ and all DBZ characters are all way too strong for any other Anime I've seen.
I would like to see a Gaara vs. Byakuya Kuchiki fight though. That'd be interesting.