Really needed:
- We need mods with warning- & (temp)banning-rights.
- We need a messaging system (PMs).
- We need more forum-sections.
- We need postcount-display.
- We need to be able to click the users name to go to their profile to see all the posts they have made. (You can only visit your own profile atm. Btw, this is already implemented: http://ace-spades.com/forums/profile.php?id=XXXX, problem is we don't know the id of the users.)
- We need a member-list which displays all registered members.
- The forums should be on top of the latest discussions. There are so many threads displayed on the front-page that users may miss that there is a forum-structure actually.
- BBCode would be much easier to use than plain HTML.
- We need to be able to use image-tags to post visible (thumb)images in our posts.
- We need a better quoting system.
- We need better search-capability (search for user-name, etc).
- We need threads which get marked with another color, icon, etc. when there are new posts inside which you haven't read yet.

Nice to have:
- The possibility to report certain posts to the mods.
- An onlinelist which displays all users which are online atm.
- A simple attachement system to upload small files.
- Some smileys (not too many).
- The possibility to have a small (not bloated) signature under the post-text (without images).
- Captchas or other custom questions to require human interaction while account registration.
- A notification email (or PM) if there's a new post to a favorite topic.
- The possibility to ignore all posts from a certain user.

Btw: Most of those idea could be easily achieved by using some plugins for bbPress.