I noticed Claus's thread re renting a car and driver and the discussion on taxis.
Taxis are a subject of anguish and salvation in Manila. Here are my observations to share with you:
1) Always look for a newer taxis - they generally have licensed, younger drivers who are honest. Older cabs often have older unlicensed drivers who are dishonest.
2) If the driver won't put the meter on then you have a choice. If there are lots of other taxis then take another. If that taxi is your only option and he says "P200 ok?" then say "whatever" or something non-committal and let him drive. Once you're there you're in a position of strength. If you know the correct fare and have the right money then just give it and walk out. If you don't have the exact money, then go to a MiniStop and get change. With such drivers always go to a place of relative safety, but always give a fair amount.
3) Know where you're going and look at a map beforehand - the driver may also be unaware. Also note that I've never seen a driver here use a map, so outside of his domain he's lost.
4) In smaller towns there are often only trikes - so feel privileged!
5) If you have trouble getting a taxi, try a jeep or train - it could be fun - but watch out for pickpockets and phone snatchers.
6) Carry an umbrella - taxis are hard to find in the rain.
I hope this helps.
P200 for that ok?