Originally posted by Rondec Remember that you are not buying a body, you are buying into a system. Look at what lenses, accessories you would get and see if you are willing to go for it.
This is very true. I would look at what lenses you're willing to buy before deciding on which system to switch to. The Canon 17-55 2.8 IS is a very good lens and probably the best APS-C normal zoom on the market. If you plan on buying FF glass I would wait on the Nikon D7000 as Nikkor's 24-70 2.8 is better than Canon's. Nikon's lineup is more geared towards FF in general so you would have a clear upgrade path in the future.
Also note that if you plan on buying glass without IS/VR just keep in mind that you'll be losing in body SR. Since SR mostly works behind the scenes, it's easy to forget it's there. But, without it, you might find that some shutter speeds you never thought twice about using are suddenly blurry. Since you need the 7D for AF speed, and therefore action shots, this probably won't be relevant but it's something to consider nevertheless.
In any event, 1,200 for a 7D is a good deal, and the 7D is a great camera. I'd say go for it--even if you end up not liking it you can sell it to get your money back. If the 7D fills your needs and the K-7 doesn't there's really no reason not to.