Lightest and easiest wiki to setup?

twiki is good.  I'd recommend Mindtouch (www.mindtouch.com).  They've got a Debian VM that you can download and run, essentially, out of the box.  

Here is a rather large list of Wikis
http://en.wikipedia.org/wiki/List_of_wiki_software

Here is a comparison of those Wikis
http://en.wikipedia.org/wiki/Comparison_of_wiki_software

how about mediaWiki, is it really tough to install/configure, do suggest, thanks.

We used mediawiki for about three years, and our experience was this:  
-Many user found the wiki markup to be very difficult (I liked it, fwiw). The WYSIWYG plug-INS were adequate, but not terribly robust.
-The lack of fine-grained ACLs was a real problem. If you need to be able to set permissions on pages MediaWiki is definitely not for you.
-The universe of plug-INS for MediaWiki is fantastic; you really can do a lot with it. But that adds to the complexity of the installation, Especially when doing upgrades.

 

nope, its just that it would need a database while dokuwiki doesn't need that

Ack. You asked about installing and configuring. Sorry.
So Mediawiki wasn't terribly difficult to install, but some of the plug-ins (like LDAP auth) complicated things a lot.

It's been several years since we've used mediawiki, and it's possible (probable) that some of that has improved.

Admin ... need some more time to test and decide, which one to select?
Thanks.