If you don't have an investment in the system, there's no compelling reason to stay with the same brand when upgrading. Since you've had your camera for a while, you should think about what you like about it and what you're missing. It sounds like there are a few things about the Canon model that really appeal to you, so that's good. I'd suggest making an even broader list of wishes (without having a model in mind) and then looking more widely at current offerings to see what fits your desires best.

If small and light is important to you, you may want to consider going away from DSLRs entirely, to something like a Micro Four Thirds camera from Olympus or Panasonic, or even Fujifilm's X100. Or, for high frame rate, Sony's SLT cameras are hard to beat. And, of course, take lens size into account as well: the Canon 60D isn't small or light with L glass attached; maybe something like the the comparable Pentax K-5 with a few nice prime lenses would fit you best.

You note that you haven't looked at lenses available. That's definitely a time to stop and step back. You've got some experience and idea of what works and what doesn't, so now you're probably going to be wanting to buy into a system that you'll stick with for a while. You should definitely take a look at How much do lens lineups vary across DSLR platforms?, and maybe this for flash as well. Don't just consider the feature list of this year's latest model. They're always leapfrogging over each other, and if you make your decision that way, you'll always be unhappy a year later. Instead, consider the system as a whole — the camera system, and the general approach of the company, and how that fits with you as a photographer.

It's probably also a good time to think about ergonomics and other little things. The controls systems on Nikon and Canon are rather different. And in my subjective view, the camera companies with less market share put more thought into this — Pentax and Olympus particularly. And Sony tends to have be very photographer-oriented, and utilitarian — which makes sense when you know that their camera division comes from a buyout of Minolta. You can adapt, but if you're really comfortable with the way your current camera works — or find it annoying — that's something to take into account. A camera that's a joy to use is a camera you'll use more. (And that alone may make it worth investing a little more than you might otherwise — something I strongly advocate at the mid/entry level.)

Of course, upgrading your camera isn't a magical path to better pictures, but with digital technology upgrades are inevitable. You might, though, want to look at whether your money is better spent somewhere else: a new lens or other accessories for your current camera. (See After 2 years of amateur photo, buy a new body or a great lens?)