I hated Palermo. With the exception of the Capuchin Catacombs (just outside of town: a quick bus ride or walk, depending upon where you stay) and the Villa Palagonia.
The Capuchin Catacombs are not for the faint of heart. Fascinating, though.
The Villa Palagonia (aka the Villa of Monsters) is in Bagheria, an easy train ride from Palermo. If you appreciate the bizarre, you'll like PV.
Capuchin Catacombs: en.wikipedia.org/wiki/Capuchin_catacombs_of_Palermo
Villa Palagonia: www.villapalagonia.it/
My Sicily trip report: www.travelmusings.net/sicily-2009/
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