At work, it's a little bit of this, a little bit of that depending on when the scripts were written. Some of our Solaris boxes have 5.00x. (5.005_03? I can't recall as it's been a while since I've had to use them.) Some of our linux boxes have 5.6.x but most have 5.8.x. Some of our WinXP boxes have 5.8.x too.

At home it's 5.8.6.