While I think that most of the posts to use FreeBSD or PC-BSD are spot on, I think I should cover what you shouldn't use in the BSD world due to your requirements.
My own os, MidnightBSD, does not have virtualbox. The nvidia binary drivers work from FreeBSD on it, but that won't be the case forever.
MirBSD wouldn't support at lot of the software you mentioned and doesn't have recent java support for minecraft.
OpenBSD might work, but you would have to check on a few packages.
NetBSD is probably your next best bet after FreeBSD due to the wide variety of packages.
DragonFly is weak on packages, although they're working on it.
FreeBSD does offer disk encryption. Note if you use encrypted swap, there is a massive performance hit. I used to have this a default in MidnightBSD up to 0.4 and it was not a pretty picture on server hardware. Sometimes you'd get panics if there was too much swap pressure with it.