When I published Awake My Soul I put it up on Smashwords and Amazon, mostly because those seemed like the best two options. For Amazon, it was a given. It makes up anywhere from the 50-75% range on ebook downloads.
Smashwords I went with because of the distribution. Through them they would upload to Nook, Kobo, Sony, Apple, and so on. Awake My Soul has been available for three weeks now and I'm just starting to see it on other sites through a TON of searching on google. I couldn't find my book simply by typing in my name or title on the sites. I had to google it to find anything, and even then I haven't had a ton of luck.
Amazon is by far the best seller, but I don't want to shut out people without a kindle. So as I find the links, I'll add them to my blog here. Hopefully that helps people wanting to buy Awake My Soul.