read up on photography a bit. you must know the basics, you can't even take great pics with a great camera without knowing what your doing.
However you don't necessarily need a dslr to take good pictures, but i recommend at least a high quality point and shoot.
I took pics like these...:
with this camera:
here are some pics taken with a very expensive dslr camera (not mine, nor are the pics):
2nd set of pics by Patrick Aalto
anyway, my point is you can get good pics off a fairly (fairly...) inexpensive camera, make sure u get a macro lens too!