Hell, I've used two MXL 990's pointed toward the audience, with the gain cranked prettty high, and it gave a nice effect - even though they were pointing toward the two separate sides, there wasn't much of a stereo image, but it rounded out the sound of the live music itself (which otherwise sounded very studio-ish since everything was close mic'd and the vocals were done on hypercard condensers). I'd say not to bother in that case with stereo, and just try an omni out - if not for anything other than simplicity of setting up one mic.