Chris, depending on how old your Nikon lenses are, they should still work with a modern dslr body, you'll just loose AF and perhaps aperture control also., you must also take into consideration that the focal length will also change, as most sensors are not full frame (35mm), and therefore there will be some multiplying of the focal length (x1.4 or more). Canon changed the mount when they switched over. The new Canon bodies are good (but I find them a bit too big for my liking). I use a D100 and a D300 at work, and I also have a Lumix G1 and a Lumix LX3 compact- both are very good, but if I had the money, I would have gone for the Nikon D300. The Nikon is also pretty quiet in operation too, and handles very well.