Been there a number of times. Don't spend long in Manila – maybe a couple of days max. Big, chaotic, noisy and dirty city. It's interesting enough, but it soon becomes "too much". It has a strong US background to the culture. A great day-trip is to go up to Mt Pinatubo, to get to it you have to go in some quite mental off-road 4×4's then a good trek up to the edge of the cone which is full of water. Stunning – and you go get some peace! (Noise is everywhere in the country!).
Carlos Celdran runs highly entertainign and interesting tours of Manila link below – thoroughly recommended.
http://celdrantours.blogspot.com/
What sort of thing are you looking for? Ther country is made up of literally thousands of islands, and they vary in "feel" hugely. You're probably advised to treat Mindanao (south) with great care, as there's a civil war going on and westerners do get kidnapped. In terms of "wow", my favourite is Bohol – very environmentally-aware (compared with the rest of the country which is not at all!), beautiful scenery, people are really laid back. It's got the chocolate hills which are spectacular. I'm not a great fan of Borocay, which has now become too touristy and is frankly a bit tacky.
I've not been, but I understand Palawan (long thin island to the west) is absolutely glorious.
Don't expect anything to happen quickly or even necessarily logically, just go with the flow otherwise it can get frustrating. People are unfailingly pleasant and polite, and tend to be exuberant. Enjoy – it's really worth making the effort to discover.