Another vote for QS8s, at least that's what I did when faced with the same choice (so I'm running M60s, VP100 and QS8's). I also felt that I would be happier with the same size drivers all round.

Besides, that way you won't feel so bad a few years from now when you weaken and upgrade to a VP180 ;\)

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8