Congratulations on getting into photography, everyone.
I would keep this for camera for everyday photo's, but would want a better setup to do things beyond great
Enjoy the D40... I do!
It's good that you're getting more into photography, but honestly, there isn't much difference between image quality you're getting now, or the image quality you get from a more expensive Nikon D200 or Nikon D2Xs other than MP. I guess you can crop more or something, but it's not as though a better camera will transform your photos into something better. Like
macdaddy121 said, the photographer takes the photos.
On that note, lenses do make a difference, because you're going to hit a wall in terms of what you can do regarding sharpness, depth of field, reproduction ratio (ie: macro work) and under certain conditions such as shooting in lower light.
To use a car analogy: (I know it's weird
) The car you choose isn't an issue if we're talking about which car will take you from Point A to Point B. Driving either a Honda Civic or a Porsche will get you to your destination. I can say the same thing about taking a photograph with a DSLR. Using a better DSLR won't affect the composition of a photo at all, as they're both very capable of taking a photo. You're the one pointing the camera and adjusting the camera settings, so both cameras will "get you there".
However, if you're NOT talking about getting to your destination, but wanting to do something very specific such as race, then obviously a Porsche is going to get you there faster because it's a better tool for the job, while the Civic isn't (even when the Civic is suped up
). They'll both get you to your destination, but if you're looking for speed and a decent time as well, the Civic isn't up for it.
If you're going to drive through rocky terrain, then obviously a Range Rover will be better for what you're trying to do. Maybe a Civic can do it, but it won't be pretty. I also wouldn't use my kit lens to take macros, just like I wouldn't use a macro lens to take a landscape shot. You can, but you won't get exactly what you want.
Don't worry about
"only" owning a D40 unless the camera itself is actually slowing you down. Some people need to adjust more than just WB, Shutter speed, and Aperture, and would have to dig through menus to adjust metering, AF modes, or to use bracketing. Or what if you need to make massive prints, or you work for a company that needs to do so with your photos? If you're in these situations, then you need to get a new DSLR.
I own a Nikon D50 which has more controls on the body than the D40, and yet still doesn't have enough control for me. So for me, I can't imagine using a D40 because I have much higher demands than I did before. For you, it may be absolutely perfect, as the extra second it takes for you to change a setting isn't going to annoy you too much.