Cebu is where the Philippines as a Spanish colony began: Magellan landed on Mactan in 1521, and Cebu City was founded in 1565, making it the oldest city in the country. Today it's a busy, sprawling metropolis and the main gateway to the central islands, with direct international flights and ferries to Bohol, Siquijor, Leyte and beyond.
Most travellers pass through. The ones who stop a few days find a very good food city, a long, mountainous island with waterfalls and canyons in the south, and some of the country's most accessible diving in Moalboal and Malapascua. Think of Cebu as two trips: the city for a night or two, then the island beyond it.