mmm, well, all those years ago (circa 89)...I had some spare cash, always wanted a good camera, went and visited a camera store and had a play with both the Canon and Nikon offerings at the time. It was really no contest - the eos630 was a better performer than anything Nikon had @ the time imho. Back then, Canon AF ruled on both speed and accuracy, and by a long mile. Nikon had slightly better metering and flash metering, but it was close. Other than that, most of the models were pretty evenly matched, maybe with the Canon being a fraction cheaper than the Nikon equivalent. It did help I guess that the sales person was PRO Canon. I look back at it now and realise how biased he was lol, and it did rub off onto my purchasing decision I believe.
I didn't invest much into Canon until 99, when I got the 1n and a bunch of L series lenses. Been using Canon since.
I personally don't like the Nikon UI, and the Canon does feel better to my hands imho. That said, for a good number of years Nikon has been the equal of Canon imho. Sure, some will say that Canon has been better at high ISO noise (and it has), but high ISO noise is not the be all and end all of photography for MOST users. Sure, some shoot at only high ISOs, but MOST people don't. Trying to get that rationale around some of the rabid Canon fans here was mission impossible.
Recent events have had me leaning strongly to Nikon - mainly cos the D3 is a better camera than anything Canon has at the moment, and the fact that Canon lied about the Mark III AF issues to consumers. Sure, some people are so biased here that they'll blindly deny that Canon ever knowingly lied, and I'll leave them to their naive daydreams.
I'm hoping Canon comes back swinging at Nikon with a nice new 1 series camera that equals or betters the D3. I'm hooked into the Canon accessories now, so it doesn't make financial sense for me to change to Nikon, plus it's early days, I really do expect Canon to come swinging back into the fray of the action vs Nikon.
I've had a good near 20 years with Canon, I love my Mark IIn to bits, even though I crave D3 performance (no more flash for macro shots, just shoot high ISO that is clean!).
edit: Plus Canon is the only lens manufacturer with a fantastic lens like the MPE-65. Canon also bundles free RAW processing software with their gear (DPP), which is nice of them.
Dave