Hotel affiliate with XML

Who has the best XML feed?

[StuffOfInterest]

Has anyone done some comparison of XML feeds from various hotel affiliate programs? I've been very spoiled by Amazon's XML feed for books and would now like to add some hotel information to a geographically targeted website.

So far, the best hotel booking sites with affiliate programs that I've seen are Expedia and Hotels.com (ian.com). I know that IAN has XML options but I'm not sure on Expedia yet. Also, I haven't seen anything to show what data is available through the XML feeds.

Any information on this would be appreciated.

Thanks.

[StuffOfInterest]

I think I should have clarified my request a little more. I'm looking more for a webservices type access (like Amazon AWS) rather than just a raw dump of data through XML. My hope is to integrate hotel information and booking into a site which already contains geographic related travel information. No need to become another hotels.com, but just offer a service to help people integrate more information into their researching.