Unless you're a neo-Luddite who refuses to modify any aspect of your computing environment beyond stock, you've got your favorite set of what I call "must-have widgets".
On the PC, my set includes things like Startdock's Objectdock, Grisoft's AVG and Catfood Software's Fortune Cookie program.
On the Mac, my set. . .
Well, I don't have much of a set. Yet.
I'm toying with things like Inquisitor, MarsEdit (which I'm using to write this post, thank you ack/nak reader for recommending it) and VLC.
Dashboard widgets don't count - even though I really like the Oblique Strategies widget.
What I'm looking for from all of you Mac-heads are recommendations for useful and/or essential utilities, widgets, Automator scripts, whatever you've found essential to kitting-out your Mac to make it truly yours.