Spot on Mat.
I started on maya 6 as I got a copy via uni.
I then upgraded to maya 8.5 when I started my PHD, as uni's got a platinum membership to autodesk and i'm classed as a member of staff i'll also get the upgrade.
I think it's not really a requirement to be up do date with the latest software, as its down to tallent/skills/ problem solving but it wouldnt harm to keep up to date with the changes.
I think I remember Jay saying that his studio was on maya 5.
"No pressure, no diamonds" Thomas Carlyle