Excellent idea Envy. I will post a huge list of mods as I am experienced with vB modifications. Just off the top-off my head is vB Experience. You can also check www.vbteam.info for custom mods such as HBD Portal or other stuff.
-Arcade maybe...
-Inventory [Where you buy things and it appears under your name]
-Point system [Where you get points for posting which you can buy inventory with]
-HTML names [Bought from points system, names in bold or glow etc =D ]
Guys don't just suggest things that would be cool to have. Like an arcade, nobody ever uses those. If someone really wanted to play flash games they'd go to addictinggames.com or something.