What Plugins Demonstrate Great WP Plugin Development? [closed]

I’m going to be tackling my first plugin soon and I’m looking for plugins which you feel are of very high quality, under the hood. Stuff I can use as an example while I design the framework for my plugin.

Any ideas? Please include what makes it a great plugin.

I can’t give you links to the plugin repo, but here are some great people who share good code (in pretty different styles) on Github. Just take a look at the repos or their gists:

• Frank Bültge
• Thomas Scholz
• Mike Schinkel
• Franz Josef Kaiser (me 😉