Regarding Photoshop, etc. You don't really need anything more than what you have. I don't do a lot of image processing, for a number of reasons - first off, I'm sort of a purist and second, I simply don't have the time. I did a little editing of the photos for my show, but it was only to do things like remove errant microphones for a cleaner image, etc. Photoshop CS has RAW processing built in, but it's not worth the money - there are cheaper and better RAW converters out there. Both the 300D and the 10D come with RAW conversion software which is okay, but then there's also products like Capture One, which I highly recommend - you can find it at:
As far as the 10D's ISO 3200 - the camera at that ISO setting is doing the exact same thing you'll be doing in a RAW conversion program, it's all software based, so it alone is not worth the upgrade. The reason you'd want a 10D is because it's more sturdy, it has twice the image buffer (9 images instead of 4) and has better control over white balance. However, know that the 10D mkii is on it's way - probably will be announced in September, and ship in Oct/Nov.
As I said, see if you can use your current Nikon lenses with the D70 - it currently is the best deal, and is significantly better than the 300D/Digital Rebel in many regards.
Regarding Photoshop, etc. You don't really need anything more than what you have. I don't do a lot of image processing, for a number of reasons - first off, I'm sort of a purist and second, I simply don't have the time. I did a little editing of the photos for my show, but it was only to do things like remove errant microphones for a cleaner image, etc. Photoshop CS has RAW processing built in, but it's not worth the money - there are cheaper and better RAW converters out there. Both the 300D and the 10D come with RAW conversion software which is okay, but then there's also products like Capture One, which I highly recommend - you can find it at:
http://www.c1dslr.com/
As far as the 10D's ISO 3200 - the camera at that ISO setting is doing the exact same thing you'll be doing in a RAW conversion program, it's all software based, so it alone is not worth the upgrade. The reason you'd want a 10D is because it's more sturdy, it has twice the image buffer (9 images instead of 4) and has better control over white balance. However, know that the 10D mkii is on it's way - probably will be announced in September, and ship in Oct/Nov.
As I said, see if you can use your current Nikon lenses with the D70 - it currently is the best deal, and is significantly better than the 300D/Digital Rebel in many regards.
Good luck!