There is really no one-stop e-tailer/retailer store. You just have to look around for a deal. Most likely that X-mass holiday is the best time to purchase the unit as they also include deals on bundles, saving you more if equipments purchased separately.
Between Nikon and Canon - only you can say what is better as the quality of the camera mentioned are very close and both are very capable cameras, keep in mind that 5D II has more pixel count as well.
You may have read this review already: http://www.dpreview.com/reviews/canoneos5Dmarkii/page35.asp
So it’s up to you what your priority is. As “The Nikon D700 benefits more from shooting raw than the 5D Mark II, showing considerably better sharpness and resolution than the equivalent JPEG, and narrows the gap between these two cameras considerably (even given the huge pixel count disparity). But the 5D Mark II shows an improvement too, easily matching the D700 on a per pixel sharpness basis whilst offering noticeably more resolution for those that need it.”
When I bouth my first SLR camera in '94 I went with Canon because of the feature of the Canon EOS A2E / 5 eye focusing, quieter with USM lense and considerably lighter than Nikon if you are carying that camera for a whole day.
And if you pay attention much of what is being use by professionals, Canon was widely use for sports (probobly because of no blackout EOS 1 RS or 1N RS) but Nikon (F5 for it's color matrix metering) for everything else.
So you have to check for yourself what better suit your needs.