I just started playing around with the Sage RSS reader for Firefox. I like it. If you check the site, there are a list of styles you can use for the reader. I think the Midautumn style is by far the best. So, with that, there were a few mods I had to make.
First off, none of the images were shown on my copy of the stylesheet because all images are relative. So, to fix that, search and replace url(nou with url(http://sage.mozdev.org/styles/library/nou. That was an easy fix and a big improvement - the read/unread images are one of the main reasons I liked this style.
Next, I thought about how I don't want to see the text for read posts. I don't see a way I can do that with CSS, so I decided to just hide all text. With this enhancement, the text will only be displayed as you hover over an item.
div.item div.item-desc, div.item div.item-pubDate { display:none; }
div.item:hover div.item-desc, div.item:hover div.item-pubDate { display:block; }
After the last mod, I started thinking that I may not want to see read posts at all. After all, I can always open them individually from the sidebar. So, I added this enhancement to hide those. Note that this will only work with the previous mod. Because of how you tell if a post is read, you cannot (as far as I can see) hide the body or footer without hiding them all the time.
div.item h2.item-title a:visited { display:none; }
Now, the only thing I can think that'd make this better would be to provide an XSL file to format the page. Well, that, and the ability to open the styled page in the sidebar. There is a note, however, on the project wiki that states you can use Ez Sidebar for that. I'll try that later.