I just posted a bug repport with Comprehensive Google Map Plugin, but after a moment of reflection, Im realising that I didn't notice the issue appear until after I upgraded to Attachements to 3.0.2. Perhaps this just a coincidence, I just hope to isolate the problem as I have begun to rely on both of your plugins for my site.
The issue is that the media manager modal ( the new one is now appearing - thanks for the update btw ) isn't populated with items present in the library when using the "Insert Media" button on posts and pages - or on the modal triggered by the Attachments plugin. The problem is resolved when Comprehensive Google Map Plugin is disabled.
Thanks for the excellent work and fighting the gremlins where they live.