The honest answer is with a Nikon D70 you really can't manually focus with the crappy viewfinder. I haven't used a full-frame digital or a D2X, but I imagine they are easier (more like a real camera) but you pay big bucks. I do like the D70 for what it is, but I don't fancy putting a $1500 28/1.4 (that is what Nikon makes) on a $800 body. I think a $800 body and a couple of inexpensive ($2-400) lenses makes more sense.

That's why I still shoot 35mm film too...