down sizing speakers/system

i currently have a mission 782, 78c, 780, Rel q150 sub, im using a denon avr3805 dvd3910 with pre outs run to arcam a85/p85, i need to downsize a bit and mainly in the speaker area, i have a set of quad lite which i use for a second system and am thinking about building round these speakers for front back and centre, i dont want to drop in quality for movies and music so any advise would be welcome as well as alternatives. it will be used in a med size room.