Ozone's Multiband Stereo Imager for sure, the best I've used so far. It's so flexible and has so many built in features it's perfect for pretty much everything

 

- Waves Center (just got this for 25 Bucks today!)
- Waves S1 Stero Imager is also very good for Widening (and also at sale right now)

- Sonalksis Stereotool is also good

- Brainworx BX Digital: impressive Mastering EQ with m/s Matrix and Stereowidening
- Brainworx BX Solo: (Freeware) A very simple but essential plugin let let's you switch between L/R or M/S Modes with a simple Widening dial.

- The Stereoimager of Ozone is indeed really nice. Especially in Version 6

- Dr.MS >> Extensive Controls. For me to many knobs at once. But definitely a reference product

But beware of the aforementioned Tone2 Akustix. I think this is a really BAD plugin. Becaue you can destroy your whole stereo-image and mono compatibilty by just turning a few knobs because it has so many parameters that influence the phase relationship between frequnecy bands. I'd say stay away from it unless you know EXACTLY what you're doing.

 

For quick stereo imagining I rock the WOK MST (basic 1 knob plugin) good with fattening multi sample layered kicks and synths
For guitars, drums, and other natural intruemtents...Nugen Stereoizer (the full version...the computer music version is rubbish)
For buses, spreading multiple tracks, and mastering I rock Izoptope's stereo imager

Looking foward o getin my hands on the psp stereo imaging kit. looks promising

 

wow, that font is a pia to read! lol

I pan everything in the mix and have one go later with ozone before rendering the final.