What do you think is the most important factor for eyeglasses?

[smart buy glasses]

What do you think is the most important factor when choosing eyeglasses frames, color, material, or shape?

I always care the frame shape when choosing eyeglasses, as I have a round face shape, which seems really tough to find a perfect pair of eye wear, last time, I chose myself a big round full-rim frame, when I wore it home, my friends all said it was really ugly on my face! They said that I should choose angular frames, due to they will hide the round shape and make it look angular. And the full rim or half rim is a best choice for round baby face people. Anyone can do me a favor? Please paste here some pictures of eyeglass frame which are suitable for my round face. Thanks.