OK - In no particular order, here's the stuff I've been working on...

unsticky posts
move threads

post views + topics / posts

mark posts as read
mark forums as read

view unread posts
view unanswered posts
view new posts
view active topics

latest post author
link to latest post

first / latest post hover preview

post reply button at bottom
return to top links
forum jump

online users
Bookmark topic
rss feed

stats block at bottom of forum?
user stats
Forward to see more post after posted
forum signatures

I have about half of these done.

/DM