Red, you've got the right idea. Two fronts and two surrounds are adequate for an HT setup and it's better to get good quality sound in those speakers rather than stretching a limited budget by getting more speakers at once. The M50s(your budget could probably handle the M60s as well) and QS4s will give you excellent sound(no HTIB around here)with adequate bass for most purposes. The "phantom" center which the M50s will form sounds just fine for music and movies, although center sound such as movie dialog will shift to the side of a listener who isn't near the center. Deeper bass from a sub is nice, but it can wait. Either of the receivers that you're considering would be fine.
