I flew ryanair a few years ago on a round trip England to Germany flight, at that time I didn't find them any thriftier then a Southwest airline flight.
Although I don't agree with charging for toilet use, I also try not to use bathrooms aboard planes... So charging for them wouldn't affect me, unless I of course was REALLY needing it. But if I was paying for it, I certainly would be demanding there be papertowels and soap (I know that sometimes these items are lacking).
I am a business traveler, and will be on no less then 6 planes this month alone, I most likely won't use one toilet, as I can usually hold it until I get to the airport.. I am more insulted by US AIR charging for a cup of water!? and I stopped flying with them. I stick with about 90% southwest Air and the rest is Delta and American.. but even those guys are getting cheap