I "scan" with my Nikon D300 and a macro lens, and the results are better than any flatbed scanner I've used. Any of the nikon 55mm-60mm micros do a great (and equal) job at between f/5.6 and f/8 (I have three from different eras). I set up a little station using the column and base from a Durst enlarger, a cheap LED movie light as a source, and an omega 35mm carrier to hold the negs. One of the reasons I'm hyped about the new D800e is for improving my "scans".
Aside from quality, the other nice thing about this method is that instead of 5 minutes per scan it takes 1/250 sec.
All of the recent B&W stuff on my Flickr site is done this way, and there are full-resolution views there to see, as well--you could even download one and print it to see what you get. The main disadvantage I'm having is that the resolution of my camera is close to the grain size of the Tri-X I'm scanning, so the grain you see isn't quite real grain---it's more like noise generated by the interference, that's what searching the tubes of the net tells me, anyway.
The major tricks I've used are to shoot the film concave side up, and flip in photoshop, and to align by focusing on a mirror sitting flat on the light or carrier, and wiggling the camera around until the lens' reflection is perfectly centered (I use a tripod head on the Durst stand, for the movements). At that point, alignment is perfect, too. Also, once you get everything set up and scaled right, the camera's AF does a great job of focusing, if you use the 60mm/AF lens.
I messed around with lenses, and the micros were the best. Normal lenses were decidedly bad, and enlarging lenses were not that great, either, at that ratio, so there's a $$$ investment. I do a lot of copy work so I'm up to my ears in micros. The 55mm/3.5 micro-Nikkor of any vintage is the cheapest nikon lens you can buy used, though--$50-80 should do it.
