My "Must Install" add-on for every installation of Firefox I perform! Rated 5 out of 5 stars
1. It works like it should. No frills, no fluff, no adverts, the only thing it does is load your home page when you launch a new tab.
2. Extremely lightweight. At only 4k I can install this on machines with limited resources, (assuming it can actually run firefox!) without worry.
3. *Every* time I install Firefox, either for myself, on a server, or on one of my client's machines, *THIS* is my "must install" add-on, even if I install nothing else.