P y t h o n best
No, Java. It's fast, compiled to bytecode and there is many libraries included + many to choose from internet. In java you don't have to write TCP client for multi-player and every OS, you could use Java's cross-platform one. Or another example: graphics. In java there is very nice builtin graphics api (probably the nicest on the world) and it's also cross-platform... Example of really good downloadable libs: LWJGL, JBox2D, Jbullet, Slick, etc...
It's really easy and fun to write in Java without needing to worry about memory leaks, writing apis, not cross platform (building 3 times instead of one time build), etc...