Canon Rebel T2i or EOS 550D is the successor of Canon Rebel T1i, one of the best selling DSLRs on Amazon.   Canon T2i has a much better movie mode and a metering system than Canon rebel T1i.  Canon T2i will be available in March 2010 at $899.99 with the kit lens 18-55mm.

Before going to direct comparison of Nikon D90 and Canon EOS 55D /rebel T2i, I strongly recommend to read more on the Nikon and Canon comparisons.  When you buy a digital SLR, you are not just buy the camera body, you have to buy the digital SLR system.  The lenses and accessories cost more if you want to take full use of the digital SLR.  Generally speaking, Canon has more choice of lenses and  accessories than Nikon, especially for the professional lenses.  But Nikon lenses are of higher image quality, especially for lower end lenses.  This has been changed recently.  Canon started to have very good low end lenses such as Canon 55-250mm. Canon’s new Canon EF 70-200mm f/4L IS USM is among the best lens on the market, according to many reviews and my personal experience.

Nikon D90 is a great digital SLR which has been reviewed extensively.   The key differences of Canon Rebel T2i and Nikon D90 are as follows:

Sensor:

Canon T2i uses a 18.1 Megapixel sensor and Nikon D90 uses 12.9 Megapixel sensor. In real life, the extra pixels might not make a big difference.

High ISO noise comparison:

Camera labs just posted Canon EOS 550D /Rebel T2i and Nikon D90 high ISO noise comparisons.  Although Canon Rebel T2i has more megapixels to deliver a big image, the image quality of Canon Rebel T2i is very close to that of Nikon D90.

Movie mode:

Canon T2i is a new camera with one of the best movie modes in all digital SLRs. Canon T2i can record 1080p video clips at 30 fps and 720p video clips at 50 and 60 fps. Canon T2i also has a stereo microphone input for the recording of videos in stereo sound. Canon T2i has full manual control and full AF during the video recording.

For  a HD video sample of canon rebel T2i:

Canon EOS 550D / Rebel T2i 1080p / 30fps HD video sample from Gordon Laing on Vimeo.

Nikon D90 is the first digital SLR with a movie mode.  Nikon D90 can only record  720p HD videos at 24 fps with a maximum length of 5 min. There is no manual control or AF during the video recording.  Nikon D90 does not have a stereo microphone input.

AF system

Nikon D90 has a better AF system with 11 area TTL comparing with the 9 point AF on Canon T1i.

Viewfinder

Nikon D90 has  a bigger and better pentaprism viewfinder with a coverage of 96% and 0.94 magnification.  Canon T2i has a pentamirror viewfinder with 95% coverage and 0.87 magnification.

Continuous shooting speed

NikonD90 is a  faster camera with 4.5 fps continuous shooting speed and Canon T2i has 3.7 fps continuous shooting speed. The higher shooting speed is very useful for sports photography and wildlife photography or other action shots such as children at play.

In addition Canon T2i has some new features such as a LCD with 1.04 million dots and 3:2 aspect ratio which is the same with sensor for better display and playback, the compatibility with the SDXC cards and HDMI port etc.

In conclusion, Nikon D90 appears to have better building quality, a better viewfinder and ergonomics, faster shooting speed and better AF. Nikon D90 has better menu, better customization, top level LCD control.  Nikon D90 is a better camera overall.  Canon T2i is a new camera with advanced features which is better for people who need a digital SLR for movie recording, who use it as the second camera back up or who use it as a travel camera.