I think I see two different posts going on in one, Todd McFarlane's Spider-Man art wise was one of the best ever, but I think the costume was just the traditional one and should be attributed to Steve Ditko. I would love to see a top 5 Spider-Man artist though, because I think Todd would be at the top.

I would have on that list Jae Lee

Erik Larsen

Alex Ross

and I might actually include Steve Ditko