Camera bodies come and go about every year to 18 months, so I wouldn't make a choice of manufacturers based on current models. One year Canon may be king and the next year it may be Nikon, but they'll both eventually offer similar choices. IMHO, SLRs are about glass. Since you said you haven't bought any good glass and in fact, even though you shoot with a Canon body, you have no Canon glass, I wonder if you've given your current body a chance to perform at it's best. I know of a bird photographer that has way more "L" glass than most people could ever afford and most of his shots were taken with a Canon Rebel.
MItchell, I just thought I'd offer a different opinion. Nikon does have some terrific features on their current models, but just a couple of years ago, they were trying to catch up with the features Canon offered. I'm sure Canon will respond to the Nikon features in one of their future models. If they don't, they risk losing all their customers to Nikon and I don't believe they'll allow that to happen. This game has been going on for a very long time and I don't think the end is in sight.