Myth #3: I just bought my N900 and now Nokia ditches Maemo and goes for MeeGo, and then announces that there is no MeeGo product for N900. WTF?
Nokia did NOT ditch Maemo; instead, MeeGo is in fact the natural evolvement of Maemo.
Nokia will not release commercialized MeeGo products on N900, but no one would stop users to install community versions of MeeGo if they wish. In such case, no support from Nokia is expected, of course.
In fact, N900 is a reference hardware of MeeGo Handset UX development.
There will still be bug fixes for Maemo 5, either from the official firmware upgrades or from the community maintained firmware.
Multi-boot between Maemo and MeeGo is already supported.