Nokia currently has a smartphone market and a medium to low-end phone market. Symbian is fine on the medium to low-end phones for at least 3 more years. Most phone geeks are uninterested in a lower end phone, and many people already know the Symbian interface. Leave Symbian with minimal development on those phones.
Nokia does not have it's own smartphone OS ready, so it needs to give users options
Ship high-end phones with Android. Make it easy in the Ovi tool to reflash phones into Maemo mode if the users want Maemo instead. Put major resources into extending Maemo. Put major resources into converging Maemo and Meego. When Meego is ready, allow Maemo/Android phones to flash to Meego. Even if this it takes until 2015 to complete, this allows Nokia to stop losing ground and create a smartphone OS. Forcing Windows or Symbian or Maemo ONLY down users' throats will push them away. Let users enjoy the high quality Nokia hardware with Android until Nokia is back in the game with it's own smartphone OS.
Reduce the number of models released by Nokia
Nokia releases too many similar phones with poor names. Pare down the product line to 6 medium/low end phones and 2 smartphones. The two smartphones should be Business and Media Player. Business would have a keyboard and focus on email and new corporate features. Media Player would focus on video, photos, and music. Release new smartphone models every 6, 9, or 12 months as a cycle. The Android operating system is already on a cycle, and Maemo could be transitioned to a cycle. Reduced choices equals a stronger marketing message for the phones Nokia does offer.
Create smaller agile teams, lose outsourcing and slow corporate culture
Actively recruit the younger, hipper crowd. Hire from within Linux strongly. Allow a lot of telecommuting, but not outsourcing. If current employees don't perform in new conditions let them go. Create small groups focused on single apps with solid feature lists for each realease. One group, one app.
Partner with Ubuntu
Join the Linux culture. Attend Ubuntu meetings, talk to Shuttleworth. Create a cooperative strategy for UI across Desktop, Netbook, Tablet, and Smartphone. Collaborate with the creative community.