Rain Gutter material Suggestion.

We're adding rain gutters on to our modern Contemporary home in St. Paul, MN. I have a friend who will be fabricating them for us. The run that we are doing based on the house design is very short so my material options are completely open.The gutters will be a basic box style to stick with the forms and shapes of the house but what material I should use is a bigger issue—I'm looking for some help regarding duablity and wear etc.

First I would want to know if I had trees in my lot and if I did how many and what kind of leaves and how big they are.....Once that is squared away then planning out design is the next step because if you have alot of trees like I do then be prepare to do alot of cleaning.....there are plenty of gutter guards out these days and if you do a custom looking gutter system then your going to have alot of work on your hands in the future in terms of cleaning out the gutters