for the northern part.. You should try BATANES ^^ also visit the honesty store there :)) people there are quite amazing and the houses also have different structures.. also you might try Sagada :) famous for hanging cofffins.. Benguet for wonderful farms and views (*especially strawberry farms)
inside the city, you might want to visit the Manila Ocean Park, the Mind Museum, the art museum in cubao, luneta park (i guess),
the southern part is more on beaches, scuba diving, hot springs (*you might wanna try the Splash Island-->cool slides ^^)
for food trips you can try the maginhawa street in Quezon City and lilac street in Marikina
check out also the buffet restaurant named 'Vikings', I think SM Mall of Asia has it.
every place here has their own signature dishes, so there is wide variety of food.. like for spicy food -->bicolanos are the best
(*but I think you'll find more interesting places outside manila)