a couple of observations.  first of all, anything that catt says about catching big bass applies, at least as far as i'm concerned.  second, if you really want to catch big fish, it's smart to focus on "where" and "when" first.  "what" to use is a secondary concern.  but since you asked, my top 4 choices would be jigs, swimbaits, plastics and live bait.  the order of preference would depend on the where and when factors.      

All my big bass came on weightless tiki stiks.  I guess they are around 5" or so.  Topwater frogs also land bigguns on occasion.