CodeSpy
Like other people said, take Chinese first because some it is basically the same.
I took this test thing on what lang. should you learn. Apparently, I should learn Jap. And that's exactly what I'm doing.
Though, sorry, I can't give you the link because I lost it xD
I don't know, because Japanese also has the katakana and hiragana, and the speaking is completely different.
It depends; for speaking, do you tend to fluctuate your voice a lot when you speak? then probably Chinese will be easier for you to speak. not being racist or anything, people i know who have learned Chinese said that that was one hard factor for them.
If you tend to keep your voice even and not big fluctuations, then try japanese first
smile
They're both awesome languages, so it really doesn't matter; i wouldn't take them both at the same time though, because like mentioned, the kanji and the hanzi are similar, but not all of them actually have a shared meaning.