"If you think open source is the end-all of software development, show me the open source equivalents of Photoshop, ProTools, DreamWeaver, MS Office, PageMaker, BBEdit, World of Warcraft, QuickBooks, FinalCutPro, Performer, and thousands of other successful applications. For every product I listed there are many viable commercial alternatives, but only a few open source ones. The few that exists can not match the capability or raw development speed of their commercial counterparts."

http://www.ellislab.com/index.php/open_source_reality_check/

Great post by Rick. Says what I always try to say but does it much more eloquently. Please leave your flaming replies on his blog ;-)

Update: I recommend reading the comments, some good stuff in there. Matt Mullenweg (guy who started Wordpress) chimes in and Rick does a most excellent job of responding.