[osflash] [OT] Suggestions for a wiki system?

[João Saleiro]

Hello,

this is completely out of topic, but which wiki system do you recommend? 
I need one with:
- authentication
- incorporated blog system (for multiple authenticated users)
- RSS for the changes
- commenting (preferably with avatars)
- file/image uploading
- easy skinning
- easy installation

Any suggestions? Sorry for this being out of topic, but it's that i 
trust you all guys... :o)

Thank you,

João Saleiro