Voted for *nix would vote for any Open Source system regardless of it being Unix or Linux anything thats not proprietary and binding to a vendor that loves DRM.. yes I am looking at you Apple & Microsoft.
As far as Distro's go I would have to go with Arch or Debain.. I tried Ubuntu and didn't really like it all that much, it's too mainstream and I got the feeling it's trying too hard to please everybody, that never works, you cant please everybody, I guarantee theirs always someone somewhere that wont like it!
---------- Post added at 02:32 PM ---------- Previous post was at 02:08 PM ----------
Linux all the way... @ backtrack user, hope you know how much of a skiddie that makes you sound dude.. Seriously, download Slackintosh, SPlack, Arch or Debian with grSecurity or SELinux and build your own pen-testing distro using their Repo if you have to, but never go with the mainstream crowd, live life on the bleeding edge... Tried Ubuntu didn't like it, it's too commercial trying to please everybody, you cant please everybody, its a guaranteed fact, someone somewhere just wont like it! Also it wont let you play your DVD's without enabling the codec libdvdcss2 to decode the DVD VOB in the first place, I don't want a distro I have to spend hours trying to tweak to get the bits I want to be working,! I want one I can set-up out the box with the minimum of fuss and have everything working right off the bat from the set go. Also try disabling services on Ubuntu and then finding you have to be a wizard at their proprietary Up-Start instead of using tried tested and true SYSV which is PURE!!!