I have somewhat of an obsession with aviator sunglasses, but the standard ones don't look good on me. The classic Ray-Bans and others like them have a straight line across the top that just looks weird on my face and completely overwhelms my features. Also, they usually hit my cheeks at an odd angle. However, due to my tireless searching, I have found a lovely pair of aviators that look good on everyone. In fact, I bet they would look good on you!
They are the Marc Jacobs Rimless Aviators, and the key (I think) is that they curve at the top instead of having that harsh straight line. Also, they aren't oversized, so they are flattering on smaller faces.
Also, they come in muliple colors. The classic brown tortoise is great, but I love the silver and white pictured here for summer.
They are $85, which I wouldn't say is CHEAP, exactly, but they are high-quality and my pair has held up really well.
(Photo from: Nordstrom.com)