If we're taking sides here, I'm all over Canon. I was a commercial photographer before Menhir was a zygote, and at that (pre-digital) time, I shot Canon for 35mm, Hasselblad for medium format, and Omega/Toyo/Zone VI for large format, using Nikkor lenses.
But I'll also be the first to tell you that I was in the minority when it came to SLRs - Nikon had around 85% of the market.
As for the DSLR/"prosumer" debate - if you have the $$$ to spare, I'd go with the DSLR. That said, I didn't initally have the cash, and started with a Canon A630; I'm now using both that and the EOS Digital Rebel, depending on need and the time I want to spend on setting up the shot.
regards,
jazz