My best advice is to focus on the monitoring chain and not various plug-ins.
For the longest time, I had wierd issues where I wanted the sound to be more wide (to me, I just wanted it to sound like other commercially released/viable CDs). I would push the panning and the plug-ins for "width" too far. The problem was, I couldn't adequately hear the real width in my monitors and instead of fixing problems by trying to make it "wider," I actually broke up the mix and it would collapse.
Very rarely do I ever touch a "widener" plug-in, and if I do, it's usually for other reasons than widening the whole mix.
So, my advice would be, instead of dropping the $$ on the Waves Stereo Shuffler, buy (or enhance) new monitors, amplification and acoustical treatment. None of this has to be expensive - something like the Wharfdale Diamonds and a cheap package of Auralex will get you going in the right direction. Then, don't be afraid to get those monitors away from the rear wall. Screw aesthetics, move your stuff into the middle of the room if you can. (Not the literal "middle" - around 1/3 is a good starting point. Many people will tell you that you need to be at the 38% point in the room.)
So, I don't know if I helped at all, but I think you'll be surprised just how good stuff sounds when it's monitored correctly.
J.