I could care less what format and version your feeds come in. RSS, Atom, 2.0, whatever. My newsreader can read them all. I have no preference. I pick atom when given a choice, because it's newer.
If you're going to offer multiple feeds, rather than giving me redundant versions of the same feed with the same content, offer me something different. Offer me feeds for each category. Offer me merged feeds for several related categories so I don't have to subscribe to seven out of eight feeds to get just the content I want. :) Offer me a feed of reader comments. Offer me a per-blog-post feed of reader comments. Thread your comments and offer me a per-comment feed of responses to that comment. :) (Okay, that one's probably overkill.)
I've been using an RSS reader for less than a month now, so I probably don't know what other readers might care about, but to me it never matters if your site wants to offer feeds in several formats.
