The obvious answer would be Mango square. That's where all the main hooker bars are located, as well as a few normal bars where you can try to pick up girls. I would advise caution there though....theirs alot of pickpockets, ladyboys, drug dealers, and taxi drivers that will try to rip you off.
Alternatively, you can try IT park. They have the park social, another bar next door, and a place called 88th Avenue/Crossroads. This is a more upscale area though....not many street walkers but.mostly call center workers and middle-upper class pinoys
Club icon near ayala mall is okay to. Mixed bag of foreigners, regular pinoys, and working girls
Sentral near Jcentre mall is good...middle-upper class pinoys. Along thst street (AS FORTUNA) they have a few asian style KTV filled with hookers, although they are expensive
Mo2 restobar is nice bar complex near parkmall and Chong Hua hospital. Eclectic mix or mostly Filipinos, from poorer people to middle class. Has a live band, night club, billards halls and ktv rooms. This is another classic spot..
Lapulapu has mactan newtown....plenty of girls there along with a nightclub called "LUX". Down the road is another nice bar called Cubana