Extensions are great but I love customizing Firefox without them. One of my favorite extensions is Stop/Reload, a simple extension that merges both buttons into a single one that toggles between stop and reload intelligently. You can replicate this functionality with a simple edit of userChrome.css file. In Windows, you can find it at: C:\Documents
http://feedproxy.google.com/~r/MozillaLinks/~3/W-ozCfn0icc/