Below is a link to a FAA brochure on sunglasses which pretty well covers most of the issues.
Personally I prefer brown lenses for their tendency to enhance contrast and I frequently find that I'm wearing them comfortably long after others ditched their 'neutral' glasses in failing light. Some people don't like the colour but I think that's something you get used to fairly quickly, I certainly do when switching colours in shooting glasses.
The more extreme red 'clay pigeon' glasses Pylon mentioned or the yellow target shooting glasses, will take longer to acclimatise, not that I’m suggesting you wear them flying.
Specifically, I've been wearing Serengeti Aviators since well before I started flying, gone back to cheapies (brown, green and grey) on quite a few occasions both by choice & circumstance but gone back to the good ones every time.
Moral of the story, if you find some cheapies you like, don't try the good ones, it's hard to go back.
On the subject of polarisation, there may be a few who are not aware that Liquid Crystal Displays (LCD) work by polarising crystals under the influence of a voltage, by polarising 2 layers at 90 degrees you block any light from the backlight and by aligning them you allow (almost) all the light to pass. (If there's no powered backlight you're working off reflected ambient light.) Throw a pair of polarised sunglasses with random polarisation alignment into the mix and you could get full transmission to total blackout. Hence the recommendation against them with any LCD instruments.
With the imminent introduction of polarised TV's (for 3D), I would expect those manufacturers that aren't already using screens with polarised displays to take advantage of the cheapening technology to produce better daylight screens.
www.faa.gov/pilots/safety/pilotsafetybrochures/media/sunglasses.pdf
Mark
BTW Arthur, those red glasses will show up dust beautifully, if it’s red dust from a ‘blown’ clay pigeon.