I'd strongly recommend against BSD...various reasons, but the availability of current binaries and libraries can be a challenge...even with ports...

I like OpenSuse a lot...and I know a lot of people have problems with the Novel / Microsoft situation, but remember that OpenSuSE maintains its own OSS code base. OpenSuSE, in my opinion, is more complete, even with a base install, than ubuntu.

Ubuntu is very pretty, and pretty darned easy to use. But you'd be hard press to tell any difference with OpenSuSE.

In the end, its largely personal preference. I think you wouldn't go wrong with Ubutntu at all... I think Fedora Core 6 is impressive, but a tad bloated for older hardware. Centos is a great for a 'server' style platform...

My only caveat with Ubuntu is that you should be prepaired to install additional packages, such as VLC for video or Thunderbird for email after the base install. That being said, its pretty trival to install that stuff...