Wiki Recommendations?

Hi all,

Just looking for a recommendation on a wiki. We've been using Instiki, but
it doesn't have all the features we want. Looking at Twiki.org, it seems
like that's a good fit.

We're mainly using this for collaborative documentation efforts. 

We require the following:
  * access control with groups & sub-sites/sections
  * search
  * textile formatting
  * wikiwords/autolinks
  * document attachments
  * email notifications
  * revision history (lower priority)
  * php/mysql with windows support

Any input or recommendations would be appreciated.

Best regards,
Brice