The 300D/350D/400D are entry level cameras.
This does not mean they cannot be used professionally. It is not the camera that makes a person a photographer, it is the act of taking photos.
As for the question, 400D vs 30D. No question about it.
If you drop your 400D you will need to buy another camera.
If you drop your 30D you will need to get your foot in plaster.
So yup, its nice and big, well built, solid, fast, comfy! And well worth the money.
I have been getting better shots since upgrading just because of being able to get the settings I want quicker. The control dial on the back is wonderful! I could never go back to a XXXD series now, too small and fiddly!
When it comes to image quality. I can see no difference between the 350D and the 30D.
But it just makes it a whole lot easier to get a great picture now.
