Open Source and Free Software

I'd say either Ubuntu or Fedora for anyone who has to ask, only because everyone on Earth knows at least one of the two, so they can get help easier. When I first started, it was all about Slackware 2.0 and Red Hat Linux 3.0 (back before the RHEL/Fedora split). I liked Slackware better, but Red Hat because the OS of choice for Corporate America (where I work), so I started using Red Hat (later Fedora) at home, just because I also use it at work. Now no one uses Slackware.

I don't care much for ubuntu. I tried it once and didn't see what was so great about it, but I'd still throw that out as an option for newbs, just because so many people use it, so it will be easier to get support.

And, really, the question only applies to newbies. Anyone who needs to ask the question really needs to stick to a popular and easy distro.