Solaris 10. Top notch OS, and comes with ZFS. As does OpenSolaris. Recommend to max it out on RAM.
Max out RAM? 16gb? How do you figure that?
Apache and MySQL will definitely benefit from it, but if you don't plan on running a busy production server, 2-4GB will probably do.
I was rather thinking along the lines of how I set up the V100 I got last year, but it supports only 2GB ;)