I'm surprised that the author replaced iTunes with Pandora when Grooveshark is so much more versatile. Plus, it can be made into a damn good Fluid app.
Additionally, some of his "replacements" are just extensions to normal processes; Hyperspaces runs within spaces, and Witch runs within Expose. On that note, though, there's a QuickTime add-on called Perian that makes the program much more versatile, and can in many cases re-replace VLC.
Speaking of Fluid - which should rightly have been in the list as a decent and free Mailplane substitute when combined with a few extensions/userscripts - why oh why is it so slow when compared to the same website running in Chrome. I was under the impression they used the same JS engine under the hood...
