I have been having a hard time determining the best wiki available for use on a website. I don't mind throwing business to online products if the wiki isn't too expensive, but obviously, I would prefer one that has a free version available do that I can play around with it to see whether it will meet my needs before I purchase. Since this website and forum seems to be one of the most knowledgeable with regard to all thing's Internet and the web, I thought I'd pick some brains here and get some valuable feedback prior to committing, that is you-all don't mind.

Oh, and I am looking to use a wiki written in php or asp preferably, though anything VB will be looked at as well.