If you can't afford M80s/VP180 then I would certainly go for the M60's/VP180. As Fred mentioned the difference between the M60/M80 is subtle, especially once the volume is turned up, but the VP180 appears to have much better response than the VP150 so this upgrade would be most beneficial especially for movies.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70