No real color, but what their eyes say is what REALLY matters. When I look into a girl's eyes and see her eyes just kinda screaming sadness or anger or hate? Not appealing. When they are positive and optimistic and happy? Ya, adorable and appealing beyond no equal.
I have hazel eyes myself. They tend to reflect what I wear. What am I attracted to the most? Green because I prefer redheads and most redheads have green eyes. I however, am not limited to, just green.
I like black/dark brown (too clear and mysterious), or gray (very unique pure nice color), blue (not really but yeah somehow I like it). But I will say it depends, I think sometimes the shape of the eyes alone may attract the attention.