The firefox gmail plugin has been working well. Too well... it's been wonderful. The auto login no longer works. Gmail have implemented a 'copy the graphic into the box' type of login which has rendered the plugin impotent.
Nasty - and incredibly unfriendly for blind people.
It's a pain really, I think they've done it to defeat 'pop goes the gmail' and such, but the firefox gmail plugin did not remove any ad revenue from gmail, as one still had to use the site to read the email.
Fortunately the plugin uses the gmail persistant cookies, so a manual login every fortnight is needed, a pain, but not insurmountable.