Metanota is designed to be a very simple, mostly plain text note taking app that syncs with the cloud (or, more specifically, Simeplenote), but it still manages to integrate several useful features.
You get three panes in the interface. The left pane shows your folders/tags so you can organize notes. The middle pane shows the list of notes associated with that folder/tag, or all of them. The right pane displays the note that you're currently viewing. It's very similar to the interface you'll find in a desktop email client. In addition to these easy viewing options, you can star your favorite notes and make them appear at the top of the list for easy access. This is my favorite feature, and wish I could do this in my email client (Sparrow) as well. Additionally, you can sync your notes every 20 seconds, email any note with a click, and search for any note or text within a specific note.
These features are particularly noteworthy because our current favorite syncing note-taker, Notational Velocity, doesn't offer them. While it's still the fastest way to manage your notes, if you're looking for a more feature-rich option with better organization, you'll want to check out Metanota. It's a free app, but if you want to remove ads you can pay $4 to do so.
Update: Whoops, sorry for the dupe! We actually posted Metanota last week and I missed it. Sometimes that happens. But on the plus side, it's a pretty great app so if you didn't see it on Friday and are catching it today then lucky you. :)
Metanota (Free, or $4 to remove ads) | Mac App Store