Hi Silent Running,
Yes do come to the Philippines!
For regular shark sightings:
Tubbataha has a lot of the usual reef sharks - grey reef, black tips and white tips, plus your resident turtles and occasional mantas, eagles rays and hammerheads. But you can only dive this from March - May and only by liveaboard. You join the liveaboard from Palawan.
Donsol Sorsogon is a rich feeding ground for whalesharks! But you can only snorkel with them, no scuba diving. In one day, I was able to swim with 8-10 sharks, I was so proud of this, but when my friends went, they had 40 sightings in a day. Darn! Season is from late Jan to May. Nearby is Ticao Sorsogon where you can dive with Pacific mantas (really huge) but currents are ripping. If very lucky, there are also sharks..threshers and hammers, but I didnt see the sharks.
I also heard that off Sorsogon, there is an island where schooling hammerheads have been found. Diving is not yet developed, but there is a researcher there and she has been studying these schooling hammerheads. Probably they moved here from Cabilao Bohol.
I have been lucky also to see the thresher sharks of Malapascua, Cebu unfortunately, sightings have not been as regular as before. But they are still there. There are also a lot of resident white tips (quite big) in Gato Island, off Malapascua.
The great hammerhead that we saw in Koalas, Anilao Batangas was like winning the sweepstakes. Just being there at the right time, right place. It was just passing by. Although from what I heard, people who have been diving in Anilao in the early eighties have seen hammerheads off Ligpo Island. Maybe, the hammer we saw was making its way home to Ligpo. Anilao Batangas has its share of resident reef sharks, most of the time, theyre juveniles sleeping under caves.
In Boracay, there is also an advanced divesite called Yapak. You can also see your big sharks here especially when the currents are running. I saw the biggest grey reef in this site.
In Puerto Galera, there is Shark cave, youll find the white tips sleeping inside.
Apo Reef is also best dived by liveaboard. Usual reef sharks plus occasional tigers and hammers if lucky.