Username or EmailPassword
Your suggested layout
looks really much cleaner. Before seeing that, I created little mockup too (with altered color for score line):
Maybe combining/advancing these ideas could produce even more "content oriented" look
What about a choice of color themes for registered users?
Even if there are only two or three choices that aren't much different than the original colors, some people might find one better than another as far as contrast, highlighting the parts they're interested in (the content, most likely) and downplaying the stuff they'd rather ignore (status/title/author bars), in order to improve readability.
Yeah, the alternate color definately helps. Contrast is much better. I like it.