I just finished (kind of) the drop bar conversion for my 1989 Specialized Rockhopper, and I thought I'd share a picture.
The current specs:
Salsa Moto-Ace Bell Lap bars
Profile Design Aris stem with Velo Orange stem adapter
Tiagra 4500 STI shifters, derailleurs and hubs
Avid Arch Rival 40 V-brakes with Travel Agents and Kool Stop salmon pads
Mountain LX M452 crank with 48-36-26 Biopace rings and UN53 bottom bracket
Ultegra 6500 12-27 9-speed cassette
Mavic XM317 rims
Michelin Country Rock 26x1.75 tires
SKS P50 fenders
Specialized saddle, seatpost and headset
Only the crankset, saddle, seatpost and headset are left from the original components. The stubby little stem is too short for me, but the only other stem I had lying around was a 110mm Ritchey Pro which was too long. I'll probably swap out the tires soon for either Schwalbe Kojaks or Panaracer Pasela TGs.
I went with V-brakes and Travel Agents because the fork on this bike is pretty flexy so I expected that cantilevers would have been a nightmare. The Arch Rivals have relatively short arms (~95mm), so I might switch them out for something newer when I have the cash, both to get a little more power and to give myself more fender clearance.
As an aside, I'm convinced that Biopace chainrings were designed specifically to make it harder to set up indexed triple shifting. I got it working pretty well, but it definitely pushes the limits of the derailleur handling both the high parts of the big ring and the low parts of the small ring.
Also, I fully expect that this is going to trigger a flood of other people posting pictures of their own drop-bar mountain bikes on this thread. Feel free to do so with my blessing.