Go. It's high level enough in terms of syntax that it's easy to build complex apps in, and low level enough that I'm able to control pointers, manually run the garbage collector, and benefit from the runtime performance.
Hell yea. Can't forget those compile times and that parallelism handling. I can't think of a language that has a better dev cycle to performance ratio.
I really want to learn it, and I understand the basic syntax and patterns. What apps did you make with it to learn it? I can't think of anything big to make.