Lean and Agile – should not be separated
Many organizations are introducing Agile practices like Scrum, XP etc. to get some more value in software development. An important area that is not covered so much with Agile practices is the more holistic view of the whole system. In many situations Agile practices are focused against the development team as the primary area and not covering the end-to-end processes involving the total value stream from problem to solution.
A combination I have seen working well is to combine practices from both Agile and Lean Software to get both the team and end-to-end processes handled in a sustainable way.
Don't only look at the team by introducing Scrum or another (silver bullet) process. You need to start changing the total system in the organization involving all people.
It is Business-IT alignment and one of the key roles is the Product Owner / Product Manager / Product Champignon etc., because this is one of the good candidates of a bottleneck for the rhythm in the total value stream.