What is the best way to transfer Thunderbird address book and files to Lucid Linux (Ubuntu 10.29) from Ubuntu 9.10?
It should be dead easy, just copy .thunderbird onto a usb stic or cd. copy it back after installing new system and then you will have all your emails plus rules/filters etc.
Don't bother backing it up. Just put all your contacts in Google Contacts and add a Thunderbird extension called Zindus. It syncs your Google Contacts seamlessly to your Thunderbird address book. You could also add the extension Contacts Sidebar, and your synced contacts will show up under your list of folders and you can search them there.
I suppose you you want to transfer everything including email. Although I haven't done this myself I found a short article about this on the web.
How do I backup Thunderbird mail and profile under Linux?