Well, you know where I stand on this, Lauren. ;-)

Some of the most appealing houses I have seen have been colors that would not be accepted by a HOA.  And I wouldn't live in a HOA neighborhood if you paid me - that's one reason I live in the country, because I LIKE variety and don't want to be mistaken for my neighbor.  And before that, I lived in Austin for decades, the city of "Keep Austin Weird".  My own home, by the way, is a subtle cream with reddish brown trim that fits the period of the house - would fit in an "old town" neighborhood in mainstream American towns (that's actually how  chose the colors, drove through Old Town here and Hyde Park in Austin and looked at what fit best, since this is that kind of house) and probably many HOA towns.  My favorite houses, however, have been painted in muted but noticeable shades of purple and other similar colors.  And, in Mexico, I delighted in the adobe homes that were painted varying bright colors that would, otherwise, have been boring, boring, boring (as Santa Fe was the first time I visited it, with their regulation that all buildings had to be adobe and all had to be one of five shades of adobe, at that) - what a breath of fresh air!  I've seen some truly ugly painted colorful houses, as well; the real issue is whether or not it's tastefully done.

However, if you have the kind of neighbors that are going to get all upset about having anything different, it probably is going to negatively impact their property values for buyers just like those neighbors, just as houses that are simply semi-clones of each other in a HOA neighborhood negatively impact those property values for other buyers. (You'd be surprised the number of buyers who tell me, "DON'T show me anything in a HOA neighborhood!  I'm not interested!")   I'm perfectly capable of finding the right home, and have done, for both kinds of buyers, by the way.  And I'm VERY good at pointing out "it's just paint, folks," if the only thing they don't like is the color of the walls (interior or exterior). 

Your comment regarding some people not realizing how color can impact their home?  Well, the people who paint their houses colorfully probably realize more than most how color impacts their home, not their investment. 

There's a book that I think you might enjoy, Lauren, to get an idea of how some folks view HOA's.  It's called The Association, by Bentley Little, and is an extreme version of how they look to some buyers.  You might find it interesting as a different perspective.

Tom, I guess I don't qualify as "the rest of us".  But, again, that's Dallas, this is Austin, I lived both places, and guess where I stayed? ;-)