I myself started real traveling around 2010. Since then, I mostly did not plan my travel, but rather used the best deals available for my off-times. The following list is more or less the result of my research over years.
I decided to split the list by language. 😉
German Travel Deals
Polish Travel Deals
English Travel Deals
flyertalk forum – premium fare deals
jetblue.com featuredflightdeals
Hi! some of the Spanish sites (first one) appear out of date…I would add Guia Low Cost: http://www.guialowcost.es/ they update the site every day with new flights and hotels….