Quality Agile Metrics

I was asked recently what metrics I would collect to assess how well an agile team is improving. I paused for a moment to scan through 12 years of research, discussion, memories and experiences with Metrics on various teams, projects and companies - mostly failed experiments. My answer to the question was to state that I presently only acknowledge one Metric as being meaningful: Customer Satisfaction.

We discussed the topic further and I elaborated some more on my experiences. Regarding specific "quality" metrics, I explained that things like counting Test Cases and bug fix rates are meaningless. I also referred to the book "Implementing Lean Software Development" by Mary and Tom Poppendieck (which I highly recommend BTW) which warns against "local optimizations" because they will eventually sabotage optimization of the whole system. In other words, if I put a metric in place to try and optimize the Testing function, it doesn't mean the whole [agile] development team's efficiency will improve.

It needs to be a whole team approach to quality and value. Specific measurements and metrics often lead to gaming of the system and focus on improving the metrics rather than putting the focus on delivering quality and value.  If the [whole] team is measured on the customer satisfaction, then that is what they will focus on. I have long since stopped measuring individual performance on a team.

I haven't stopped thinking about this question though, so I put this question out on Twitter this morning:
Aside from Customer Satisfaction, are there any other Quality metrics you'd recommend in an #agile environment?