Ayone know any good Spanish restaurants in Amsterdam??
Or Argentinian or Mexican?

Oddly enough, there is a restaurant that specializes in Spanish food right in the middle of the Red Light District. It is called Centra (Lange Niezel 29) and gets a good review in the Eyewitness Travel Guide.

I think I've been to that Spanish restaurant (though I don't recall the name). Anyhow it was certainly in the barrio de la luz roja, and came recommended in guides, so it's probably the one. It was very Spanish, run by a Spanish family, and very busy. Worth a visit, if you can get it. We shared a table.
(I cannot help but recall that another night on the same visit to Amsterdam we ended up in an cheap Italian restaurant. There was a TV on in the corner, and at about 11pm they started showing porn movies, which rather put me off me garlicky bread sticks! This did NOT happen in the Spanish restaurant!)

If they were showing the movie for free, I don't think they counted it as "porn." You have the "pay-per-view" option for the really hard core stuff! This was no doubt light hearted, wholesome entertainment A lot of Americans we traveled with were shocked by the likes of that while channel surfing! Europeans tend to be a lot more liberal than we are!

I went to Iguazu - a really good Argentinian restaurant. The steak with chimichurri sauce was fantastic and shouldn't be missed, but they do have a decent range of stuff.

It's at Prinsengracht 703 - definitely check it out...