As a follow up to the preview release of Firefox, and my recommendation that you keep track of every installed extension in case the install goes awry (as it did for Pamela), I am posting a link to a new extension: ListZilla
which “Outputs either a plain text, vB code, or HTML file that lists all installed themes or extensions.” That sounds much easier than doing it by hand!
One note, the description says that it is only for current releases of Firefox, so I am not sure if it will work 0.8/0.9, or just the preview release.