I have thought long and hard about this before posting, but couldn't keep it in anymore.
Before I explain my issue, let me clarify my terminology:
On SO/SF/MSO, at the top you have what I would call sections: Questions, Tags, Users, Badges, Unanswered
Then within each section you have tabs, so for example in Questions you have newest, featured, hot, votes, active and an optional 'stats' when you have a tag selected.
So with that in mind let me explain my issues.
I would like to see additional tabs under Questions for unanswered (no answers added), and unanswered (no answers accepted). This is in part due to the confusion caused by the Unanswered section, which actually lists questions with no upvoted answers (by design as stated here).
I have stopped using the Unanswered section as heavily as I used to, because it wasn't showing what I wanted (questions without an accepted answer), and maybe under this new concept, the Unanswered section (no upvoted answers) could become merely another tab. After all, the Questions and Unanswered sections aren't areas of isolation, in fact one is a subset of the other, whereas Questions, Tags, Users and Badges seem to sit well as separate entities.
Also I have often wanted to switch between Questions and Unanswered sections, whilst maintaining whatever tags I had selected, but having these as tabs under Questions, I think would alleviate that issue too.
This merely represents my user experience since joining SO/SF/MSO a few months ago.
Does this make sense?