I have read the numerous comments on the fact that we should be planning Wikimania well in advance, and I fully agree that choosing the city for Wikimania 2008 sometime at the end of 2006 or beginning of 2007 makes perfect sense, and we have started working on it.
Just for the record though, Wikimania 2006 was only the second edition, and I wish people would remember that when planning 2006, we did not even know whether it was going to happen at all. So please keep that in perspective. There is room for improvement, and I believe Wikimedia has done a good job in trying to keep everyting into consideration for the next editions.
On the subject of size. I am personally not in favour of an *international Wikimedia conference* (keywords international and Wikimedia) that will hold more than 500 people, ever. The reason for this were clear last year, but even clearer this year, ie. opening the conference to 1000 people makes it, in my opinion, lose the "Wikimedia" touch, by bringing many people in who have in the end nothing to do with Wikimedia. Mind you, I find the interaction with other organisations and people with different web, collaborative, knowledge experiences very fruitful and interesting, but this year showed a trend that I wish we did not facilitate too much. There were many many local (as in US) people who had but a far fetched interest in our projects, and thus did not pertain to the "Wikimedia Community" or had no intention of ever pertaining to it.
My dream is that Wikimedia got their hands on enough money in due time to provide scholarships to far away contributors wherever they may be and make sure that the core attendance of the conference is filled with Wikimedians.
Basically the real question is what do we want Wikimania to be? Is it the ultimate wiki conference? Is it the Wikimedia conference? Is it a free knowledge or access to knowledge conference? Is it an open source conference? Is it all of that? Some of that?
In my opinion, and in an ideal world, Wikimania would probably almost be booked solid before registration even happens, because we have managed to bring in all the people that count in the Wikimedia community.
I would hate to see Wikimania be taken away from the Wikimedians. I would hate for it to be so big that you would not have a clue who this or that person is, or worse, that some people would come to Wikimania and ask "what is Wikipedia?". I believe we have shown the world that we can put together interesting programs and that we should use this opportunity to make sure we provide different events, aiming at different publics. I would love to see a Wikimedia Academic Conference, or a Wikimedia Wiki Practices Conference. I would also love to see more regional Wikimedia conferences, such as the Chinese and Dutch edition this year who would bring together people who did not make it to the international conference or who need to concentrate in a language or on specific projects.
In short, I do not think that Wikimania would benefit from becoming a huge thing that everyone would attend because they happened to be in the neighborhood.
Delphine