Now Liquid SOnics has another free plug and a bunch of pay plugs, but I'm reviewing the Reverberate LE.  The plug is VERY easy to use.  It's a convolution reverb that is VERY easy on the CPU/RAM.  Even REAPER's own ReaVerb uses more CPU/RAM than this (sorry Cockos).  This is a good one.  (don't forget you'll need impulses to use this).

LiquidSonics site