sizz, i just posted the mango salsa recipe under misc. category.
for mangoes, i've never had one that was metallic tasting. not sure what could have caused that. i've had ones that had hints of pine, but never metal. it could be one of those genetic things, like many people experience with cilantro.
to choose a mango, they should just give a little when pressed. if they are rock hard, i usually put them out on a window sill until they feel a little soft. they are getting overripe when you begin to see the skin wrinkle a little. that's ok to use when making salsa. however if the flesh starts to turn dark instead of a brighter yellowish/orange, then it's probably gone too far.
also, if they just give a little, and have a slight, sweet mango-ey smell, buy it immediately. the sweet smelling ones are usually very sweet inside, just like picking a melon.