New Airfare Search Tools
Check out this new innnovation from farecast.com:
You can type in your origin and destination and a set of dates - and it will tell you the best time to actually purchase the ticket. An interesting idea, instead of scouring everyone's airline on the planet with search engines; time your purchasing time so that you get the best deal.
I've also added easyjet.com to my airfare search engine list (in the left column on this page) which is a great option for taking cheap european flights.
Source: Claudia, thanks!