As it happens to have it, I work on wikis for a living. Not a bad way to make a living.

As you can probably already tell, the choice of wikis is broad and vast. When you're choosing your own, you have to prioritize what you like and choose accordingly. Just as some quick, easy answers, the following are some of the best "n00b" wikis:

MindTouch
Wikia

If you're willing to do a little bit of programming/CSS/HTML/javascript, I'd recommend:

Mediawiki (Free, but has a slight learning curve)
MindTouch (Again, but it has a *major* learning curve as there's an entire programming language behind it)
Drupal (arguably not a wiki, but might suit your needs)

If you'd like to PM me, I can advise you further.