Corel Draw is slated to be released real soon now, coinciding with the
release of QuickDraw GX. The latest MacWEEK stated that it might be
released sooner without features that take advantage of it.
Canvas, Illustrator, and Freehand are probably the most complete
drawing packages around for line and color Postscript work. As there are
at least 20 or so other packages out there, you would probably do well
to determine what sorts of features you need and see if you can stand the
interface and implementation before buying it...
You would also get a much larger response to your questions if you posted