You could also check [Cityjet][1]. They used to be an air france, but changed owners recently.

Furthermore, do check all, because depending on dates you want to fly all might be the cheapest. Personally, I avoid Ryanair, just to avoid the hazzle, but if you are strictly abiding to their rules, and buy checked luggage ahead of time, they might be the cheapest

  [1]: http://www.cityjet.com