well, i don't think that it's necessary...
scriptblocker doesn't work in vista (when UAC is enabled) and i never really needed it in older OS...
the ms-outlook/exchange provider is a nice thing, which adds some interesting features
firefox is (like IE) protected by the webshield and thunderbird is (like windows mail) protected by the internet-mail-provider and so i don't think any more plugins are necessary - but would be a nice extra...
just my thought
yours
onlysomeone