The most famous and busy gelato place in Corfu is this old one. It's also located along the main thoroughfare which certainly helps too. Other than a well staffed gelato area, there are also cakes which I didn't try but looked very nice.
The gelato is an extremely generous serve. The £1.70 cone with 1 scoop (they let me have 2x 1/2 scoops) is a huge amount with gelato stuffed in all through the cone. I tried the dark chocolate which was thick and good, but the pistachio was pale, weak and a waste of time unfortunately.
If you want only gelato, go to Solo around the corner.