Yes, u can buy just the rear speaker. There are 2 type of rear speaker in the market; direct or bi-pole/di-pole. For direct, you can use those small book shelf speaker. The surround sound will be directed to the listener ear. As for bipole or dipole, the sound will be more disperse as it will reflect off the wall. You need to test both type to see which one you prefer. As for recommendation, u need to specify your budget. Go to Amcorp Mall and test out some speaker there if you are from kl.

My personal preference is bipole/dipole as I prefer a wider sound for the surround. You can consider Mission MH3 or Wharfedale WH2. For small book shelf, can consider Mission M30i. CMY is selling the same OEM (Denon SC-M51) for only RM390.

http://www.mission.co.uk/model.php?model_i...id=2§or_id=
http://www.e-cms.biz/temp_1.asp?categoryx=29&ProductID=194
http://www.cmy.com.my/index.php?page=stock-clearance