[SLUG] Wiki suggestions? (DaZZa)

[James Linder]

I'm looking for a Wiki to setup for the company to make available to

contractors semi-private documents
I don't mind if I have to pay a little for it, but open source would
be most excellent.
So, I'm looking for suggestions for some form of Wiki.
I'd like
1) Secure - two levels of access (view/edit)
2) Lightweight
3) Linux (obviously, 'cause f**k paying Microsoft tax where I don't have to)
It'd be nice if I could integrate it with AD (or at least LDAP query
for usernames/passwords), but that's not critical.
It'd also be nice if I could put some kind of skin or theme on it
customised by the marketing nazi's to make it look all company-ie.

What colour car is best?

I find mediawiki easy to use, to maintain and my 5 min of fiddling painted it in a form that pleased me
http://tigger.ws/wiki/index.php5?title=Main_Page

James