That's tough! I agree that Kamayan and Cabalen are two of the best Filipino restaurants, but I'm not so fond of the overly traditional presentation and ambience. Sometimes, you just want to eat good Filipino food in a lighter and more casual setting.
The best Filipino restaurants that fit the "light and casual" category best for me are:
1. C2 Classic Cuisine (6th Floor, Shangri-La Plaza Mall, Mandaluyong) --modern twists on traditional Pinoy food. My personal favorite there is their reinterpretation of ginataang tilapia (tilapia cooked in coconut milk).
2. Cafe Ten Titas (4th Floor, Gateway Mall Cubao, Quezon City) --really, really good food at affordable prices! the idea behind it is fun as well--the owner is basically reinterpreting classic Pinoy food with the help of her ten titas (aunts) who are Filipino but live and work all over the world. My favorite dessert there is the turon with leche flan inside (bananas and rich custard wrapped in spring roll wrapper then fried).
3. Ebun (Greenbelt 3, Makati) --I don't know if they're still open, though, i haven't been there in nearly 2 years. delicious food in a vintage-y setting. their tables remind me actually of tables my lola had in her house. my boyfriend hates pinakbet (a mixed veggie dish) but he loved the pinakbet there.