I've chaired / been an advisory member / been involved in organising many conferences in my time. I was asked recently for some thoughts about conferences. Beyond the usual of having a theme, a story for the day, good speakers, a comfortable environment, an excellent AV crew etc ... there is a particular structure I enjoy.
a) Scene setting / opening keynotes
Introduction to themes. This should be very much broadcast mode, high level, fast paced and using humour. Often I introduce a group of lightning talks and if necessary a vendor 'red card' system to prevent pitching. Key for me is to leave the audience with a good grounding in the themes.
b) Hegelian dialectics.
Usually two to three sessions using a format of thesis, antithesis and synthesis on 'hot topics' e.g. "Will robots replace humans?", "Is bitcoin the future of money?", 'Is disruptive Innovation just the latest hype?" etc. One speaker proposes for 10 minutes (thesis), one speaker opposes for 10 minutes (antithesis) and then both speakers debate and discuss with audience for usually 20 minutes (synthesis). I find this good for sorting out the chaff from the wheat and getting people to realise there isn't usually a simple "answer" to complex problems i.e. thinking caps required. With good to speakers who know their topic well it gives a bit of challenge and often peps up the audience in the bargain.
After grounding in the subject and discussion on a few controversial hot topics then there's nothing like a bit of practice and real world examples of use. Customer stories, leading users in the field etc.
d) Res, non verba.
Ok, I never call it this but where possible I like to introduce an element of session choice i.e. two simultaneous tracks. This is the conference equivalent of A/B testing and tells you a lot about what topics matter but also the composition of your audience. Both want to cover part of the theme and ideally you want them to be both top notch i.e. don't give the audience an easy choice.
e) Audience Panel ('meet the experts')
As we move towards the end of the day, the key thing to focus on is reflection. I find that letting the audience speak to each other about the themes of the day is helpful in building up a real community and interaction within the group. The format I normally use is randomly selected audience members to make the panel (4-5 ppl) and allow an ebb of questions back and forth between panel and audience. This is probably the most difficult part to MC effectively.
f) Closing thought
The toughest bit, done at the end of the panel, a thank you which summarises the themes discussed and leaves the audience with one key point to think about.
Anyway, that's my preference. Things which I don't tend to enjoy and in my view should be used extremely sparingly (if at all) are 'expert panels', 'fireside chats' & 'product pitches'.