Dont forget publishers that don't play on amazons table but still support the format. Particularly Baen. VERY easy to get kindle formatted books from them and they have LOTS of freebies, particularly the first book in a series. Highly recommend the Honor Harrington series (Start with On Basilisk Station) and the monster hunter international stuff.
Black Library puts out lots of Games Workshop Warhammer/40K stuff. A bit pricey for me, I guess the brits are used to higher prices, but still better than lugging around an actual book.
As for the indie books, I find that with rare exception the skills and talent of an editor (or even proof reader) are sorely missed. The big publishers add more to a book than just marketing and store end cap space. Hopefully someone will start offering quality editing/proofing to the indie guys for a reasonable price. Heck, I wish the kindle allowed for user submitted proofing, I'd do it for free on the stuff I'm reading!