It really depends on the guy. Every guy has different tastes. I know tons of guys who love girls with blonde hair and blue eyes, but I personally am more attracted to exotic girls, (different ethnicities and whatnot).
If you're trying to find out if you're attractive to guys or not this isn't the way to do it. Everyone has different tastes, and if you're on this planet, there's someone out there who will think you're beautiful, that's just part of life! :)
Natural blonde hair and blue eyes are most common in the upper midwest. But so many girls everywhere use bleach, that it's kind of the norm. Many have such naturally fantastic black hair and dark eyes and it makes me crazy when they want to go blonde and wear colored contacts. Chances are they still look good, but not the same as they did. It also depends to some extent on whether you also change your style of dress or retain some native culture. Give me black hair, dark eyes and Latin garb any day. Throw in an accent, move to some Salsa and I'm yours.
Well. I definitely have the exotic look. And though I don't hate it and never will (because its who I am). There are times when I wish I had a bit lighter skin and blonde hair and blue eyes. But I have a tanned skin, brown eyes and yes, I am a brunette. I think it depends on the guy. Some guys love the typical american girl and some guys love exotic women. Most of the guys I am around love the exotic look and then I also have some friends who love the blondes. So in all fairness, different guys have different tastes.
I think they want what they don't have. My boyfriend is blond hair blue eyed, I'm Dark haired and dark eyed.