Fed up of typing https://bugzilla.mozilla.org/show_bug.cgi?id=549867 ?
Firstly, it’s a great idea to set up a “bug” keyword in Firefox. So you can type (or, often more usefully, paste from an email) “bug 123456” into your URL bar and have the Right Thing happen. The URL you need is:
Right-click, select “Bookmark This Link” and type “bug” into the “keyword” box.
Secondly, the handily-named bugzil.la URL shortener permits e.g.:
(Thanks to Reed for making that happen.) This is good if you are attempting to squeeze an important message into, say, 140 characters. In case anyone was wondering, “.la” is Laos.