I found Calliga in the supermarket in Sidari. I brought a couple of the rose home for my birthday in August.
The Ruby is nice too, I can't remember if I saw any of it though.
Any of Kef's white Robola's are usually ok too.
The smoothest white wine we had on Corfu was a locally made one which I immediatley forgot the name of (can't do lunchtime drinking any more). I never saw it on any of the menu's but Nathan might be able to tell you the name, I think it was Ritsos or Pitsos or something similar.