Mac OS X/Safari only: Opening multiple tabs from anywhere except the browser is painful. You click, Safari pops up, head back, click again, ad nauseum. John Gruber has coded a workflow you can install to open multiple URLs with a Control-Click.
The script, courtesy of Gruber's blog Daring Fireball, only installs on Mac OS X running Snow Leopard (10.6), and can only open tabs in Safari. That said, if you're all-in on your Mac, gaining the ability to launch all the links in any area you select — emails, documents or PDFs included — without having to make return trips could easily become a daily time saver.
The script is a free download, and the source code and instructions for building one yourself for Leopard (10.5) are included at the post.
Service: Open URLs in Safari Tabs [Daring Fireball]