CANON 60D or CANON 600D?

I would say no on the Nikon. Not that they're bad, but Canon is always top of the line when it comes to anything with photography. The 60D is the better camera, but the T3i is also awesome. You really can't go wrong either way. Kind of depends if you're more of a beginner user or an advanced user. If you're a beginner go with the T3i because the options will probably be easier for you to figure out.