Things I have learned about effective sysadmin meetings
We've recently started having some regular meetings at work, which has given me an opportunity to look back at past meetings and reflect on what I think does and doesn't work in meetings for system administrators. (Note that I am pretty sure that some of these do not generalize to other sorts of meetings.)
Meetings can be an efficient way of holding discussions, but you need someone to corral the digressions. They are not usually an effective way of giving status reports, unless the status reports are really the starting points of discussions; otherwise, it's better to email everyone the status reports beforehand. Remember that people read faster than you can talk.
(The two classical cases for useful sysadmin meetings are making a decision and figuring out a problem; both benefit from the very fast back and forth you can have in a meeting.)
Meetings do not create social interaction or bring people together in and of themselves. Meetings can create social interaction if they cause people to work together, but you need something for people to be working together on to start with.
Meetings run much better with an agenda and someone who can push people along the agenda. Write the agenda down where people can see it; a whiteboard is better than in email, because it's right there in front of people and you can do things like erase a topic that you're done with. You don't want a chair so much as you want a moderator, someone to watch for when discussions are digressing and cut them off or redirect them.
Always have a time goal for the meeting. Announce that the time goal is less than the amount of time you have the room reserved for, and that the extra amount of time is just in case.
If you do not write minutes in some form, you have not really captured the information from the meeting. Don't try for comprehensive minutes, just go for enough to job people's memories, but do clearly write down any decisions and things to be done. If you're actually writing something for people who weren't at the meeting, you need to figure out what information they actually need from the meeting, and write up just that; comprehensive minutes are unlikely to be it.
(Comprehensive minutes exist not to transmit information but to allow blame to be assigned later by precisely identifying who said and did what. This is why they are carefully taken by political committees and board meetings.)
See also Greg Wilson, but note that he is talking about meetings for programmers, which I feel are somewhat different. In particular, if you are kicking around a problem it can be very handy to have a laptop or two that you can use to look up any additional information on the spot, instead of having to stop the meeting, go off to get the information, and then come back later.
(I tend to feel that if people are distracting themselves with laptops, they are not sufficiently involved in the meeting to actually be present and you might as well let them take off.)