Having been on several panel presentations, wireless lavs and SM57/58s on
desk stands seem to be the standard, but for permanent installs you may want something better.
Unless you can get everyone to wear a
headset or lavaliere mic, I personally prefer short goosenecks with the caridioid or even mini
shotgun mic capsules for conference tables.
Audio-Technica,
Shure, AKG, Clock Audio and others offer these.
Flat mount boundary mics can work well, but have limitations in some conference table applications. One if the biggest is that they sometimes get inadvertently covered with papers, notebooks,
etc., then people wonder why no one can hear them. People also tend to push low
profile mics out of the way to set down their coffee or laptop and the users often don't realize they have a front, especially with the circular mics. If you try to
cover too large an area with a
boundary mic, such as an "omni" (actually only half omni since it's on a table) in the middle of the table you can start to
pick up lots of extraneous noise. A gooseneck, even low
profile, helps make people think "
microphone" and they inherently know what it is and that they talk into the end of it.
There's a lot more to a Constellation
system (or
LARES or ERES) than multiple mics. Area mics can be very effective, but can also add a lot more work for the person mixing.