Updating an old recommendation:
For anyone in Ottawa, if you are new to the area (or new to rabbits) and are looking for a good rabbit vet, I'd recommend Dr. Daren Auger as one of the best in the city. He is the vet I initially recommended here some time ago, but his location has moved. He now practices here:
Carling Animal Hospital
2268 Carling Avenue (at Woodroffe)
Ottawa, Ontario K2B 7G1
There is another vet at this same clinic I would recommend alongside Dr. Auger: Dr. Keith Johnson is a co-owner of the clinic and he has treated my rabbits in the past. He saved Yofi's life a couple of years ago after the boy developed a mysterious and rather deadly infection, and I can't say enough good things about this veterinarian. Both he and Dr. Auger are extremely well-knowledgeable with rabbits; when a difficult case is presented neither one hesitates to get opinions from other rabbit-savvy vets if needed, and both of these men are absolutely wonderful with their patients as well as with the owners. They are well worth taking your rabbit to, for illnesses as well as overall general health care.