[da BaSsTaRd!]

in my (limited) experience with waves S1 (stereo expander), it made my mixes sound a little "out of focus", especially drums. you're probably better off experimenting with panning than looking for a quick fix with a plugin.

you know, a little chorus on guitars and bass really creates a wide stereo field. just keep it to the bare minimum so it doesn't sound too chorus-y...