I would agree that the food sold by Ryanair is really bad (and expensive).

I have much better experience with Virgin Express (which is not a "true" LCC, but which is significantly cheaper than traditional carriers). Their on-board choice is limited (sandwiches), but certainly better than Ryanair.

They also offer the possibility to order food with http://www.alphadlish.com/ who offer a quite good selection. I have done this several times and was quite pleased.