Got heaps of advice myself from a range of ppl leaning towards Ray-bans or Serengeti's... was advised by optometrist ppl to look for non-polarised, grey/green lenses (don't get too dark when overcast nor brighten things up unrealistically)
I ended up picking up a pair of Arnette's.. thin metal frame so easy fit with headset, and can get away with wearing them when not flying too... so can't complain too much, after seeing how some of the alternatives looked on me they would have been be strictly cockpit only (although I know that we don't really worry about those types of things, do we?!
)