Probably over ambitious, impractical and pointless, but this is a thread to index the type of threads that already exist, or for people to ask if a thread has already been made regarding a specific topic before starting a new thread. Try not to get over specific (specific band threads that can be easily searched), covering more abstract/hard to search for topics. For example:
Covers: Really Fucking Good Cover Versions.
Best of lists: So It's Halfway Through 2011 ; The Coachella Forum Official Top 10 Greatest Albums of All Time ; The Coachella Forum Official Top 10 greatest bands of all time.
So yeah. Contribute as you feel fit. Or don't. This is bound to fail.