The Zoom H4 is very popular these days.

You're not clear on some important points...

Are you simply sitting in the audience and trying to record the sound in the room? Are you going to place a mic directly in front of or directly upon the person doing the speaking? Will the person be speaking through an amplified system, and if so, will you have access to the sound feed from that system?

The Zoom unit can handle most of those situations through its input plug, too.