Ok then; let's see:

So you've already got a good sub, and a VP150 center....good start

You don't care much for the sound of the M3s; that's cool, lots of other folks(other than ME, don't either!!) So you may want to take a look at the M60s at that! The M50s sound like the M3s, but the M60s sound like your new VP150, so that's good match!!

It also sounds like your room is border-line in size for being either too large or not too large, so perhaps M22s would work as well! And they would also match up well with your VP150.