Source: http://feeds.feedburner.com/~r/lifehacker/full/~3/304903206/gmail-right-click-menu-speeds-up-navigation
Firefox with Greasemonkey: The Gmail Right Click Menu adds a custom right-click menu to your Gmail inbox to take you to common Gmail navigation points. Currently that includes most of the links in the default Gmail sidebar, like your inbox, starred email, and drafts, along with a quick compose link. The script is still very new, but the developer has plans to incorporate labels and keyboard shortcuts, making this one very cool and promising script. Gmail Right Click Menu is free, requires Firefox with Greasemonkey.