TeamBurns

To change the order of the accounts in Thunderbird:

1. Shutdown Thunderbird
2. Edit ~/.thunderbird//prefs.js in GNU/Linux, C:\Documents and Settings\\Application Data\Thunderbird\Profiles\****.default\prefs.js in Microsoft Windows XP, and C:\Users\\App Data\Roaming\Thunderbird\Profiles\****.default\prefs.js in Microsoft Windows Vista and 7.
3. Edit those the following 2 lines to change the order of the accounts. The default account is always first one.

user_pref("mail.accountmanager.accounts", "account5,account3,account2");
user_pref("mail.accountmanager.defaultaccount", "account5");