Is there a widget for Mac OS X dashboard that has bigger sticky notes?
I'm using SimpleNote on my Mac and iPhone for pretty much all my note-taking. It automatically syncs notes between computers/devices, so might not be for you if you only want local notes. I find it's really convenient for accessing my notes everywhere, though.

It doesn't look like big sticky notes, instead you get a list view of your notes with a preview, from which you can open the entire note. I find it really pretty, but it might not be the aestethic you're after.

Edit: Forgot to mention that I use the DashNote widget on my Macs. There are other options as well, but they mainly come as stand-alone programs.