Snow Sports:

Once again, the choice to go polarized or not is more significant than choosing a lens color.  On bright sunny days, polarized lenses are your best defense against glare and "bounce back" off the snow.  The Lens Material link on this site discusses polarized lenses and snow sports.  Many opticians believe that polarized lenses work great on sunny, powder days, but make it harder to recognize ice patches on other days.  We have thoroughly tested this theory, and we believe this is a load of poop.  Glare doesn't help you see anything.  It prevents you from seeing hazards in or near the source of the glare.  In spite of this opinion, polarized snow-eyewear is almost impossible to find.  You can find them on this site by going to the Ski Goggles link in the Find your Glasses by Activity section and limiting your search to polarized glasses.

Copper, and shades of copper, provide excellent contrast and depth perception in bright snow or flat-light conditions.

Rose tints also provide excellent contrast, especially in flat-light or low-light conditions.

Note: The Smith Ski Goggles Rose Copper-36 is one of the most perfect lens tints for improving vision in snowy conditions.  This Rose Copper tint exists in several degrees of darkness in the Smith line of goggles. Ignitor Mirror is the most popular.

Yellow lenses provide better contrast in low-light conditions, but provide minimal protection in bright sunlight.

Amber or brown work well in a variety of lighting conditions.

Gold is kind of a yellow shade of copper, so it will provide contrast on brighter days and improve vision on low-light days as well.

Grey is NOT recommended for skiing or snowy conditions.  Grey will maintain true color, but does not increase contrast.  If everything is white, contrast is very important.

Panoptx has created some great lightweight sunglasses with goggle-type padding to give the look of designer sunglasses with the functionality of a conventional goggle.  Copper and Polarized Copper lenses are available in most models. 

Water Sports:
Polarized lenses have the greatest impact on vision, regardless of color.

Grey is best in deep-blue waters, and for maintaining true color.  Grey is also a good choice to reduce eyestrain during long-term wear in any environment.  (See Kaenon Kore)

Copper, Amber, or Brown lenses work well in shallow water.  Copper provides the best contrast with the least color distortion. (See Smith Reactor D-Max)

Yellow or Rose are best suited to low-light, or early morning conditions. Don't wear yellow in bright light.  (See Kaenon V3)

Golf:
Choose a golf lens that wraps around your head, or protects your eyes from all angles.  Those tiny flat frames that are so popular for street eyewear do not belong on a golf course.  If light is reflecting off the back of the glasses and into your eye, your sunglasses are not protecting your eyesight.

Shades of Gold or green provide the best contrast of the ball against a blue sky.  Gold shades also improve depth perception. (See Bolle Kicker)

Grey provides the best contrast looking down the fairway.

Blue tints highlight the ball on grass or greens.

Rose tints provide great contrast on low light or cloudy days.

Photochromic lenses adjust for varying light conditions.  Photo Brown will provide more contrast than Photo Grey, but you will probably not have this option unless you are purchasing Rx lenses.  

Amber or brown polarized lenses will help you find your ball on the bottom of a pond.

Bolle has a goldish-brown tint called EagleVision that is designed specifically for golfers.

Driving:
According to industry estimates, 18 - 20 thousand car accidents a day are attributed to glare.  Polarized lenses have the greatest impact on glare, regardless of color.

Amber or brown provide natural contrast and help block glare and blue light.

Grey, once again, is an excellent neutral color that blocks all the bad stuff (like blue light) and lets in true colors.  Grey is also the most comfortable lens for extended exposure to the sun.

Green highlights many of the colors that occur in nature.

Serengeti is a long-time favorite of drivers and pilots.  Their patented "Drivers" lens is available in a variety of frame styles, with or w/o polarization.

Hiking, Hunting, Wilderness:
Red tints provide the best contrast when looking at any green background.

Amber or brown provide excellent depth perception against a green grass or blue sky background.

Yellow lenses block harmful blue light, and enhance an orange target for shooters.