My main work server (solaris) has 5.005_03, which is why I installed 5.8.4 (the newest at the time) in my home directory.

My work machine booting in WindowsXP always has the latest ActiveState release (currently 5.8.6), booting in Linux has 5.8.5 (preinstalled with fedora 3).

My home mac has 5.8.5; had to build it myself because the Apple installed version has threads switched on, which DBD doesn't like.

My laptop borrowed from work also has ActiveState 5.8.6

...so to summarize, generally the latest stable release.