I really like the stickies that come with OS X. I know there are some more advanced "to do" lists, but I kind of like the simplicity and solid design / ux of the native ones.
How can I synchronize stickies between Macs?
How about using Notational Velocity instead?
alternate (newer, better maintained): http://brettterpstra.com/project/nvalt/
You can accomplish very basic synchronization via services like Dropbox.
This method is effective, but not very robust. Stickies saves all stickies in one file, and blindly updates it whenever you make a change. And file sync services will not merge a single file, but outright replace it (although they will try to avoid losing your data if changes are detected on both machines).
So, this will only work properly if Stickies is closed on other machines when creating, editing or deleting notes.
Take a look at this app:
It looks just like stickies and has the functionality that you are looking for. And it's free!
Hope it helps.