Don't get a used camera because from what I've seen, people want too much for them. If you get a new one or last year's model on sale, you'll have something pretty versatile that you will find fun uses for.

Canon or Nikon, you'll be happy with what you get.

Get good software. You don't need the latest wiz bang Photoshop unless you're a pro who works for corporate clients. CS2 is free, sort of and works pretty damn well and you get pretty professional results for the home/hobbyist shooter. The software that comes packaged with your new camera will get you started but you may wish to get some really sharpened results with other software capabilities. I say this because once you start getting into sharpening, you'll wonder what you did before without it.