There are plenty of good macro lenses for both Nikon and Canon, but you might take into consideration the sheer convenience of having an articulating screen for tripod shots and low-level or high-level shots. This is a truly back-saving invention. Also, because most of my critical manual macro focusing is done on live view in 5x or 10x mode, I think that an articulating screen is much more useful than a 90 degree optical viewfinder attachment.
As far as 1:1 macro lenses go, for the APS-C format, the Canon EF-S 60mm f/2.8 macro lens is the one to get for copy stand work. For off-stand work with better working distance, most people go for the Canon 100mm f/2.8L IS, an earlier non-IS version, or one of the Sigma macro lenses, for example, Sigma 150mm f/2.8 with or without IS.
MP-E 65 is an "advanced" macro lens for those who want 1x to 5x magnification in the field, without having to putz with bellows. If you like to putz with bellows, Nikon has several good bellows that can be had on the used market, and one of the Nikon bellows models has front tilt/swing, I believe.
Both Canon and Nikon have excellent macro-specific dual flash systems. Or, you can cobble together your own flash brackets and diffusers, a favorite hobby of macro photographers. (How many diffuser variations can you make out of household trash? Lots!)