If your room is relatively large I would go for a real good sub, with another vote for EP500. If your room is small you might get more benefit from the QS8s, since they really give the illusion of a larger, more open listening area.

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