Wiki recommendation

[Neerav]

The wiki for this project had to be killed off last year due to inability to adequately safeguard it from spam. I would very much like to restart the wiki. However, I feel that Wikimedia is overkill, too heavy, and too complicated for our needs. Any suggestions from experienced users?

Requirements/Preferences:
1) easy to update/upgrade
2) no real need for mods, should be useful enough out of the box (like phpbb3 which includes text challenges, etc)
3) elegant, pleasant, powerful, yet very easy to admin the site, review/approve changes, etc.
4) remember, this is essentially a one-man job, so the solutions but be easy and convenient. Building a moderator team has fallen flat a number of times.

There are so many wikis out there, it's difficult to decide. I don't want to settle on one, use it, and then have to move everything to another wiki system later for some reason or the other.

Suggestions, experiences and assistance very much appreciated. Let's get this project back on the road and cruising at a nice speed!