Mark Pilgrim, a high-profile blogger and life-long Mac user who recently caused a few ripples by switching to Ubuntu Linux, has written a nice list of essential software for Linux. Since he's coming from the land of iTunes, iPhoto, and Mail.app, the list is skewed toward Linux apps that replace (or at least approximate) their OS X counterparts. Pilgrim's picks include digiKam for photo management, amaroK for music, and KMyMoney ("like Quicken without the monopolistic dickwads"). However, there's a few apps he hasn't found an equivalent for, namely iMovie and Quicksilver ("Damn. I miss Quicksilver."). Head over to Dive Into Mark for the complete list.

In other news another notable Mac user, Boing Boing's Cory Doctorow, is also about to make the Mac-to-Linux switch. I'm with Jason Kottke, who says, "If I were Apple, I'd be worried about this."