I use M22ti's as mains with a VP150. EP350 and QS8's as surrounds. Considering your current setup and use I'd have to say upgrading the surrounds to QS4's or 8's would give you much more WOW and upgrade impact than getting the 60's. If you were a 2 channel nut with a serious hankerin for redbook material then maybe 60's or 80's. I have a huge room and my M22's are perfect. Look here

http://www.axiomaudio.com/images/ee.jpg

Best of luck.

M22ti's, VP150, QS8's and EP350!