What features do you like or use in other forum systems that you think would be a good fit here on DaniWeb?

That's a hard one, you have already included most of them and made them look user friendly.

How about a top chart for: endorsements and total rep. points.

An app (if you want to stand out)

How about a daniweb wiki page? I think that could be very time consuming... but it is a pretty cool feature that some forums have like php.net

At the risk of sounding like a complete suck-up, I rarely use other forum systems except for very specific questions (to a vendor, for example) and I have yet to see one that has anything I would like to see implemented here.

An Android app!

Most of the forums I visit are based on vBulletin. DaniWeb is already better than any of them.