I used to work for Ryanair and let me tell you, I'd never fly with them having seen how things work on the inside. That aside, their prices are not actually low as many have pointed out on here. Yes, the actual ticket price might be virtually nothing, but as soon as you pass through the booking process and added luggage etc, it's not so appealling.
I am off to AGP soon so thought, shop around and see. My findings:
All inclusive return prices (ticket, baggage, taxes etc) from LGW, for one adult:
Ryanair £93.50
easyJet £62.40
Aer Lingus £67.40
BA Not available