You're choosing 2 pretty tough languages to learn.
I speak a little German - it's a pretty complicated language for an English speaker to get their heads around in parts, even though a lot of th vocab is quite similar. Chinese grammar is very easy but the different tones can be tough, Japanese grammar is also pretty easy but the alphabet can be tough because there are three of them. I speak a little of both but not well.
Not that I speak them seriously, but I thought the latin based languages are fairly simple. French, for example, was much much easier to pick up than German has been (I've forgotten it all now though), and I've been told Spanish is also pretty straightforward.
Most important language I think would be Chinese. If you look at history, we've been through Spanish dominated centuries and we're just leaving the English dominated 20th century. China is waking up and developing quickly. Half of Australia is already Chinese owned. The 21st century is going to be where China makes it mark on the world and knowing the language can only help get you ready for that.
IMO.
