denon x 3600 h

Well , I own an X3600 H Denon AVR , my room is a rectangle shape with 3x6 meters. Right now I am using Mordaut short Aviano 6 as fronts ,5 centre speaker and aviano 2 as surround with Jamo 112 subwoofer x2 . I am looking to upgrade my speakers and subwoofers, so any suggestion will be more...