3.5.1 Has now been set as compatible with Thunderbird 8 on AMO so your Thunderbird should silently re-enable AttachmentExtractor if you have TB8 installed.
Warning!
1.3.5.1 doesn't really fully work with Thunderbird 5-8 - there are a number of errors thrown and its probable that some functions won't work but there was a large demand for an update and this was the quickest solution.
I've rewritten large parts of the code in 1.4 but there are some features missing so its not been released yet. Its available as a beta in the Development Channel below if you want to give it a try. As your preferences are migrated in 1.4 you will loose them if you decide to go back to an older version afterwards.
Just select the messages containing the attachments you want to extract and select 'Extract Attachments' and this extension does the rest. No more having to go through each message to extract the attachments!
Check out the settings dialog for the different options.