At the moment I'm using OpenBSD on my laptop. The reason I chose OpenBSD is, it ran very nicely on my Mac when I first decided to wet my feet with a true Unix-like OS (not Apple's OS). It's been running pretty nicely overall, but I have come to miss some things I have become accustomed to, like a journaling file system and the ability to load adobe flash content (I can load videos that use flash version 7, but that's about it). Oh, and I don't want to have to compile Java again
So, I plan on backing up my user files, and installing a different OS. Initially, I was thinking about PC-BSD, and then I was thinking about OpenSolaris, but increasingly, I have been considering Linux.
The main choice of linux distributions for me at the moment is between CentOS and Ubuntu. I'm leaning towards Ubuntu, since apt-get seems to have very good package management capabilities. On the other hand, I remember an incident a while back where a Debian developer screwed up OpenSSL and, well, I found it worrying that something like that could happen.