Character Logo: If its a character logo, I would prefer it to be an ocean themed character, mainly an octopus.
Letter: I think a letter logo that focuses on the Q could work really well.
Abstract: I think an ocean theme (wave, palm tree, etc) abtract/line art logo might work as well.
Typography: I think good typography alone makes logos really good, so I would be happy with even just a good text logo.
Overall, I'm not really sure what I want on the logo, only reason I mention ocean stuff is because i'm an avid scuba diver and live in Florida, I'm not sold on the idea of it being ocean themed since it has nothing to do with the business :P
You could focus on "bringing people together" type design as well, since thats what conferences do.
Maybe something about communication/networking since thats what conferences are for.
Majority of meeting planners are women.
A more fun/whimsical logo is preference over an overly business logo.
Should look good on white and black backgrounds, should be simple enough to work on a business card as well as a logo of a website.