I am guessing from the way you asked the question that you either don't need corrective lenses or that you wear conctacs.
If that is the case buy GOOD sunglasses and learn to take care of them. One of the big reasons to buy GOOD ones is so that there are not distortions in your field of view. You may not notice them but often times cheep glasses or glasses with to much of a "base curve" will tend to distort both your periferal and your depth perception. Neither of these distortions are good when hunting.
I was ignorant of this until about 10 years ago when I finally had to break down and get glasses for distence. It was a real revelation as soon as I got them as to how much my visual acuity had deteroriated. Everything was crisper. The glasses I got were very light and thin and there was little curvature to them.
I followed them up with sunglasses, mostly for fishing because I really do not like sunglasses in the woods. Sense I was buying them mostly for fishing I went for a model that wrapped the face to block out as much side light as possible. This helps when looking at fish in the water.
What I noticed immediately though was that because the "base curve" of the sunglasses was different from that of the regular glasses I preceived a distince shift in depth perception between the two. The flatter glassses produced depth perception that was equil to my regular vision. The sunglasses on the other hand had a much greater curve to the lenses and that was anoying.
I noticed it the most while fishing. Every time I switched to the sunglasses from the regular glasses my casting accurecy, as far as judging distance, went into the toilet.
Finally got rid of the more curved sunglasses and replaced them with a set with flatter lenses. That solved most of the problem. I would second the Costa Del Mar as a good brand with a very good warrenty/service reputation. I use their aviator style with sidesheilds for fishing and they are very good.
Lots of the guys around here, NE FL., also like the Ocean Waves brand. They too have a good record on service and warrenty.
Buy good ones and be sure there is NO depth perception change before you buy them.