I make recordings that are quite realistic and satisfying with:
Soundman.de OKM Klassik-Studio omni mics--in-ear things that look like earbuds, a little over $100 and could hardly be stealthier. Or Church Audio CA-11 omnis, about $130 + shipping.
Church Audio CA-UGLY battery box, $30 + US shipping (9V, Soundman maximum is 10V) or SoundProfessionals SPSB-10 (12V for the CA-11), $60.
Sony PCM-M10, for which you'd now have to substitute something newer that's similar--Roland R-05? the new Zoom F1?--about $200.
Or buy Pillowman's PCM-M10 in the Yard Sale!
http://taperssection.com/index.php?topic=185682.0A live recording from the audience will never be a controlled studio recording. But to me getting away from talkers/whoopers/singalongers is far more crucial than a giant equipment upgrade.