1. No slandering/insulting others because they happen to like different styles of music than you. What you consider the worst song in the world could be someone else's favourite song, and they don't deserve your abuse just because they expressed how much they enjoy it. Put someone in their place only if they are truly being ignorant, but don't get on someone's case simply for stating a preference.
2. No "what's your favourite song/album/artist" threads. The [url=http://www.vgchat.com/showthread.php?t=72]Musical Favourites[/url] thread was designed for the very purpose of keeping the board from being cluttered with "what's your favourite/best artist/album/etc." threads.
3. Take a good look around on the forum before making a new thread, as someone else may have already created one on the same subject. We don't need more than one thread on the subject of Mudvayne, for example.
4. If you're going to make a statement like "power folk aluminum metal rules!" tell us why you think so. Put a little thought into your posts.
5. Enjoy yourself.
Expanding on what Shin-Ra said, in the Currently Listening thread:
I want to see at least two posts between each post you make. Or an hour plus at least one post between each. Simply to cut back on the "spam" as it's not necessary. I especially don't want to see double posts with five minutes separating them.
Since it's obvious most people won't put a lot of thought into their posts in that thread, this is the next best way. No substance, fine, but don't go crazy because I will delete as many posts as I care to that break those simple rules. They really serve no purpose than to bump up your post count, since I'm sure no one cares what you're listening to every five minutes of the day.