What factors determine the prices for DSLRs?

Okay, so i'm new to DSLRs and i'm also planning to purchase a DSLR. However, after doing some research, i realized some cameras are more expensive than the others even though they don't offer as much pixels. For example, Nikon D7000 is more expensive than Canon Rebel T2i (body only) but T2i has a better senor by a bit however, the price difference between the two DSLRs is significant. Why is that? Is it because of the shutter speed, ISOs, and FPS?

Also, as i mentioned early, i'm planning to buy a DSLR and i'm looking into the Canon Rebel T2i. Is that a good camera? I know the Canon T3i is coming out very very soon but it's an extra $200 in Canada and they offer pretty much the same thing so that's why i want to go for the T2i.

I do plan on taking a lot of photos with my DSLR, and also doing some videos with it so i'm looking into a DSLR that offers 1080p video recording.So… Is there a better alternative? (Price has to be around the same as the T2i.)

It would be great if you people can help me clear up those questions…

You should buy this one camera

Nikon D90 DX 12.3MP Digital SLR Camera
* 12.3-megapixel DX-format CMOS imaging sensor
* 5.8x AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR lens included
* D-Movie Mode; Cinematic 24fps HD with sound
* 3-inch super-density 920, 000-dot color LCD monitor
* Capture images to SD/SDHC memory cards