Both make great systems.
Nikon IMO has the edge in the lower end DSLR bodies. I like the layout of the Nikon system much better than Canon. Coming from an SLR system, Nikon has a more traditional layout, however once you get into DSLR's they are complex compared to their SLR cousins.
Another thing I like much better about Nikon is the software. Canon tends to have a more processed image. Some like that, others do no. Canon has the edge out of camera in high ISO shooting IMO. The in camera sharpening is a lot more aggresive vs. the Nikon. This means that if you shoot a lot at high ISO's, the Canon image generally requires less post processing.
All this said, I know a number of pro's who shoot with a D70. I do not know of any pro's who shoot with a D300 (Rebel DSLR). Nikon chose to really load the D70/D70s with high end features, where Canon chose to dumb down the D300.
This is a highly subjective decision, so I've attempted to provide information in the area's where the bodies differ. From a lens perspective, Nikon tends to make better WA optics, but both systems have an awesome lens lineup that will break any photographers bank.