As you wanted some opinions, here are mine against your lists, (of course these are just my thoughts /experience!)
White Sand
+ looks a LOT better
(subjective... looks nice when it is new, but despite stiring mine, having trumpet snails, corys, and plants, mine started to form black patches within the sand, and the surface of the sand showed every little tiny thing that landed on it)
+ easier on corys
Again, it's a bit of a comparison. Yes they like to dig in it, IF you can keep it all clean. The films I've seen of corys in the wild have never been on a sandbed, but just a common mud river bed. I honestly don't think that smooth fine gravel is any worse for the corys than the sand. In fact if I was to rub a handful of sand through my fingers, and then a handful of my gravel, the sand definitly felt more abrasive to me...
+ once it settles it will keep looking like the day i bought it
as long as its clean
Yup, it's just the end of that sentance you have to bear in mind 
- harder to clean
I have to agree, it used to take me ages 'hovering' the pipe above the sand, to remove the rubbish, then recovering the sand from the bucket, rewashing it, and adding back to the tank :roll:
- a little pricier since i cant find white play sand
- could be problematic for the filter
- be very careful when cleaning the glass, sand has a nasty habit of scratching, and it's not as easy to see when you have some trapped against the glass as it would be with gravel
Black gravel
+ much easier to clean
Yup 
+ a little cheaper
Perhaps, of course it all depends on what sand you price up and what gravel you price up.
+ wont be problematic for the filter
- wont look as good, but the black will contrast the colorful fish i'll likely have
Again, subjective, personally I would disagree here, I really prefer my darker substrate
- probably will eliminate corys from my tank even though they'll probably be fine. i just dont want them if they cant dig around in the sand
Get a fairly fine black gravel. The stuff I have, (Roman Gravel), is quite fine, but is also pretty lightweight, (when I washed it I had to actually persuade some of it to sink!). All my corys seem to be quite happy sifting through the top layer, although obviously not as deeply as they would in sand.
- has the possibility of the color chipping away, would could add debris and degrade the visual quality
Depends on what you buy. I have had my Roman Gravel in for around a year or so now, and it still looks as good and as black as it has ever been
+ I find it easier to plant into gravel than sand, as things actually stay rooted, (although this could be overcome with sand if you use plant weights).
+ Gravel tends to stay where you put it, both day-to-day, and also when refilling the tank after a waterchange. Conversly, I used to find the sand would shift, even just in the flow of the filter.
As I say, those are just my thoughts, but it gives you a different opinion to your own from someone who has tried both.
If you click in my signature there should be some pictures of the tank with the black substrate in the thread, (the early photos have 'natural gravel', which I decided I neither liked the colour of, nor the size, weight, or roughness for my corys!
