My website is all forum based, so I have a few suggestions that my members are constantly pushing:
Customizable content on profile (Where you are from, age, website, location, work, relationship status and such)
Direct Messaging. I know this is already being voted on, however I feel this is VITAL to the success of my website, it is requested daily.
That's it! That is all my members are asking for on a daily basis on www.SimpliPost.org
I would love to see these incorporated.