You asked SLR or DSLR, which ever is best. SLR usually refers to film camera where as DSLR is a digital camera. (Technically speaking, SLR refers to both)
Which do you want? I prefer Nikon F100 (which is a film SLR) with B&W film in it but that's my preference. With F100, there is nothing I can't do, equipment wise. It's just a matter of knowing how to do it - which meets your requirement of "growing with" the camera.
With your budget, you are pretty much limited to a low end digital gear or a really nice film gear. The choice really is yours.