Arch Linux.

It's fast like Slackware (which I liked when I tried it), very customisable by using PKGBUILD/AUR (similar to Gentoo portage, which is amazing for absolute control) and has an excellent wiki (https://wiki.archlinux.org/).

You'll also get the most up-to-date packages, and roll along happily.

If you feel you need a little more stability, then go with a Gentoo or Funtoo Stage3 install. :-)

Re FreeBSD, the best thing about it is the Port system, but you'll likely be hating the non-GNU userspace!