Which new OS should I move too?

I need a new OS on my main box. Something technical that will give me a more in-dept knowledge of the technicalities of Unix and Linux.

I'll be attending a grey hat boot camp in a few weeks. What should I compile?

I'm a newbie to network OSes and the only Linux I use extensively is Ubuntu.

>>7
freebsd is faster than linux, more stable than linux, and easier to install than most linux distributions. if you want really easy, pc-bsd is easier to install than ubuntu. freebsd also has a linux compatibility layer that can run linux binaries, often faster than linux itself.