SnagIt equivalent for Mac

I love SnagIt for the PC. I’m using it for this book, and I’ve included a description of it in the book, as one of the tools covered. It’s a great screen capture tool.

Only problem: no version for the Mac.

Does anyone have any suggestions for a comparable tool for the Mac? Other than Grab? What I’m looking for is a tool that not only does the great screen captures in multiple ways (window, selection, timed, desktop, paged), but also provides the post-capture annotation, such as the nice looking arrows, cursors, and graphics, as well as the tasks such as select and magnify, and so on.

If it has a download trial or is shareware or even free, all the better.