The height of the tourist season is also the height of the music season in Santorini. If you are here in July, you may want to take in the annual Santorini Jazz Festival (www.jazzfestival.gr), which has been bringing international jazz bands and artists here every summer since 1997. Many performances are on Kamari beach. In August and September, the 2-week Santorini International Music Festival (tel. 22860/23-166), with international singers and musicians, gives performances of classical music at the Nomikos Centre in Fira. Admission to most events starts at 15€ ($20).
Fira has all-night nightlife; as always on the islands, places that are hot one season are gone the next. I'm not listing phone numbers here because phones simply are not answered. If you want to kick off your evening with a drink on the caldera, to watch the spectacular sunset Franco's and Palaia Kameni are still the most famous and best places for this magic hour; be prepared to pay 15€ ($20) and up (and up). If you are willing to forego the caldera view, you'll find almost too many spots to sample along the main drag and around the main square, including the inevitable Irish pub, Murphy's. Kirathira Bar plays jazz at a level that permits conversation, and the nearby Art Café offers muted music.
Discos come and go, and you need only follow your ears to find them. Koo Club is the biggest, whereas Enigma is thronged most nights. Tithora is popular with a young, heavy-drinking crowd. There's usually no cover, but the cheapest drinks at most places are at least 10€ ($13).
Out on the island, in Oia, Zorba's is a popular cliff-side pub. The fine restaurant/bar 1800 is a quiet and sophisticated place to stop in for a drink -- and certainly for a meal.
Kamari has lots of disco bars, including Disco Dom, Mango's, Yellow Donkey, and Valentino's, all popular with the youngish tour groupers who grope about here.