Thunderbird Global Inbox
When Creating a new POP email account in Thunderbird you may want to have all accounts in the single Local Inbox rather than separate Inboxes for each account. It's not immediately obvious where to set this.
Go to Tools... Account Settings... and Server Settings... for the account you wish to set. Clicking the Advanced button will give you a popup where you can set the radio button to Inbox for different account and in the drop down box select Global Inbox (Local Folders).