I liked the speakers we had (only got to Calfo's, but heard others were good too).
However, another thing we could do to have added value would be to have the area's record demostrations throughout the year.
Examples would be tank drilling, propagating corals, ect....
After editing these, you could make them into presentations for use at the next fest.
Then we could have these running on a cycle on computer for viewing, kind of like having virtual speakers.
Guess this depends on having a second conference room, just a thought.