If you want to treat yourself, go Gold Class.
Knox is meant to be the largest cinema complex, but the last time we went to see a movie there, we had to wait a few hours to be able to get tickets, and then we got stuck right up the front row.
(Also located in defect central)
Never had a problem with Dandenong cinemas, clean, comfortable, and hardly used!
We went to see Matrix Reloaded the day it came out, and there were maybe 15 other people in the cinema.
A couple of websites that might helpp you decide are
http://www.villagecinemas.com.au/
&
http://hoyts.ninemsn.com.au/
You can also pre-book tickets online so that you won't miss out.