Nikon and Canon DSLR sales were always pretty close during the last 5 years.
Canon did dominate many sporting events because Canon viewed heavily discounting their equipment to these organizations as a marketing cost. A friend of mine in India told me that some of the major news organizations actually got the equipment for FREE in return for using the equipment and wearing Canon vest and hats at major sport events there. I know in America, even the Nikon shooters have to wear Canon jackets to shoot on the sidelines of NFL games. Canon also had slightly better low light performance and had IS super telephotos until the recent Nikon lens upgrades. But, the momentum has swung back to Nikon now. When the 2008 DSLR sales numbers come in, I'd bet my life that Nikon has a significant lead worldwide like it does in Japan now.
Frankly, NONE of my friends that shoot Nikon are thinking for switching to Canon, but several of my friends that shoot Canon ( and Minolta and Pentax) are thinking for switching to Nikon. In Australia, at a wedding I attended, the Canon pro took the best picture of me I have holding my D3 with the RRS L bracket and Perfect Portrait flash ring and the Lightsphere flash diffuser on top of my SB-800. I must say this guy was probably the best wedding photographer I've ever encountered. Most of them not very good, IMHO, but this guy understanding of composition and light made me envious. I wish we had more time to talk.
D3, D300, D2X & D200 New 14-24 F2.8 too! If your not shooting Nikon your doing it WRONG!