Originally Posted by Happy

<snip>
If you are looking at exploring Sicily - you may want to do a bit more research - Palermo over Catania, Syracuse and Noto from Catania are far nicer, ditto Taomina.

Taomina is thought to be The town in Sicily to visit if you can only visit one town... I would not agree with it 100% but it definitely is a lot nicer than Catania.

With our almost round the island drive I would rate the cities and towns in Sicily in that order - Palermo, Cefalu (can easily take a train from Palermo), Taomina, Syracuse and Noto, (they often are mentioned hand in hand), Catania, and Messina being the last.
The must visit sites are out of any of the above cities / towns -
Villa Romana del Casale
Valle de Templi (Valley of the Temples - the Unesco site is modeled one of the temple ruin on this site)
Monreale Norman Church (there are buses from / to Palermo for a day visit)
If one has more time, then add Segusta (quite near Palermo airport about 50 miles drive)