My Missoni aviators are timeless. I will wear them until they fall apart. They've had a few accidents in their time; most noticeably the time I ran over them with my car! Oops.
Aviators are not for everyone, but I think they suit my face. I bought a pair in H&M when I was 15 and ever since they're my go to style.
I do have a few other pairs, but I keep going back to my Missonis. It was hard at first to spend a bit more money on shades, but they have never had a screw come loose, their legs have never bent and I've had them for 3 years. The lenses are scratched a little, but I'm sure I can take them somewhere to get them fixed.
These were my 2nd favorite pair, but they fell apart in my purse after 3 wears :(
I also really like the look of...
Christinas round frames
Heart shaped frames a la Katy and Kelly
and totally retro cat eyes (Not sure who this chick is but I LOVE everything about these).