Hint: Always negotiate your cab fare before you get too comfortable - otherwise rider beware - no meter means you are in for negotation agony!
Ecuadorian taxidrives are a bit of a pain to deal with - especially if you don't speak the language. We've been charged rates left, right and all over the map.
Our final cab ride took place at 4:30 AM. He wanted $7; we settled for $6 even though the last time it was only $4.00 - however it was better than our first original fare of $10.00.
Now if you are landing at the Quito airport the taxis will charge you $10 - but, and this is a very easy way to save $6 - take a two minute walk (if that) - simply cross the airport taxi lane to the next road. There will be a set of lights - and hail a taxi there (as it is most likely there are cabs waiting for you).