There are many ways to search Bugzilla, each with a substantial following.
If you're already familiar with Bugzilla's fields, this is the fastest way to search. The search boxes in Bugzilla's header and footer are QuickSearch boxes. Assign it a keyword!
Includes form elements for many of Bugzilla's fields, as well as "boolean charts" that let you do complicated searches with any Bugzilla field. Includes some keyboard shortcuts, but still much more mouse-dependent than QuickSearch.
Visited a bug recently, and want to get back to it? Just type a word from its summary into Firefox's address bar and let the awesomebar find it for you?