Shiny user titles, the ability to warn/ban users, and the Mod Cave.
That's really all the difference. It's special, yeah, but not super-special.

In terms of index page, nothing, however moderators can edit and delete other user's posts instead of just their own. They're just like other users however have a coloured rank which is to let the newbies know who to contact if they have any queries or questions. I imagine "being on the staff" would be no different than being a regular user, only you might get a few more PMs and are "in the know" about major site/forum works that may be held.