Update 05/11/2011: This plugin has been updated to work with WordPress 3.0 and above.
Although I like the new look of WordPress 2.5, I miss having the visited links in the dashboard shown as a different color. I like to keep up on the latest WordPress news and I previously relied on the link color to see what I had not yet read.
Fortunately, WordPress 2.5 has a way for plugins to add additional color schemes. So I whipped up a quick plugin to add the style necessary to mark those visited links in a different color. You can grab a copy from my downloads page for Admin Colors Plus Visited.