From experience in East Africa, the good old green back is King. Most places don't know - and definitely don't want any Euros.
And a lot of places, around here at least, are very, very suspicious of any US $ notes older than 2000. It used to be 1996, but recently banks and forex bureaus aren't keen on any currency before 2000. Old, torn, faded notes are also not welcome. At best they will screw you on the exchange rate for these notes, and at worst will reject them out of hand.
So brand spanking new US$ (but not fake ones!) will get you through most places here.... Bon Voyage!!!