DSLR Camera help: Which one to choose?

I'd like to get your opinion on these cameras in which I'm considering about buying for my class and for personal use. If you can, please give me your opinion and which one you would recommend. Also, if there's any camera you would suggest that I have not listed.

I'm not sure on which camera to purchase but these are my options:
1. Canon - EOS Rebel T3i 18.0-Megapixel DSLR Camera
2. Canon - EOS Rebel T2i 18.0-Megapixel DSLR Camera
3. Nikon - D5100 16.2-Megapixel DSLR Camera
4. Nikon - D3200 24.2-Megapixel Digital SLR Camera

Added (1). Also, I want to start taking HD videos and I'm more of a portrait girl rather than scenery.

Being a Canon guy I recommend any model in the Canon Rebel line from the t3 to the t3i, depending on what you can afford. All of the newer models I've named do HD video.

Any one of these with 18-55mm will get you started.

YOU have to make the choice, find a dealer who lets you handle them and pick the one that feels best.

Well specs wise the D5100 is the best out of those. It outperforms the others in terms of dynamic range and ISO.
All of the cameras you mentioned record HD video. Canons are usually considered to have an edge when it comes to video quality. The image quality of the T2i and T3i is the same. I'm not sure how the D3200 compares since it just came out but I don't expect much difference there either.
For a beginner they're all great cameras, so it doesn't really matter that much. Just pick one.

All the cameras you've listed are very close (with the D5100 being slightly better) so just pick the one that feels good in your hands and that you find more user friendly. Go to a store and try them.

By the way, you can also get a 50mm f/1.8 lens, which should be a very good portrait and all around lens. It's also great for just learning about aperture and depth of field, and a fast lens like f/1.8 will let you keep your ISO lower and minimize the image noise. It's perfect to get you started. That's just if you have some extra 200 bucks to spend. Nothing wrong with the 18-55mm kit lens for start.

The Canon Rebel T3i is the best choice. Better to get a camera that does awesome in both photos and videos rather than get a Nikon that only does good with photos.

I would recommend the SONY SLT A57 and the SONY NEX7

No one can give you the right answer. Because no one know the right answer. Canon man will recommend Canon. Nikon man Nikon. Sony man Sony.

It would be better if you find any known to you who have DSLR cameras of your choice. Spend 10-15 min. With each camera. And then decide which is better for you.

Above mentioned all cameras are exactly same. Interface or menu of Nikon and Canon is different. Some expert recommend canon because canon has in built auto focus motor which make its lenses inexpensive. But i have compared the lenses between Nikon and Canon. And I found Nikon lenses more inexpensive.

Between T3i and D5100, D5100 is better and cheap than T3i.

T2i>D5100>T3i>D3200

T2i is first because it's like the T3i (newer model), but only doesn't have an articulating screen and is the cheapest. D5100 is close behind it; it has better technology, but is more expensive.

D3200 is just too crammed with megapixels I believe, D3100 would be much better.

Here's a DSLR Buying Guide - http://www.the-dslr-photographer.com/2009/11/which-dslr-to-buy/

Go for Canon EOS Rebel T3 it shoots great! Detail is way better than I expected for a "consumer" model. For the small price, Canon EOS Rebel T3 camera really packs a big punch. It was a no-brainer for me to choose Canon for my first DSLR. Every single camera I've ever owned is a Canon, and I've never been disappointed. This camera is great for the beginner photographer, and even for the more advanced photographer. It's a breeze to learn how to work all of its functions and most importantly, it delivers such amazing quality photos. The kit comes with 18-55mm f3.5-5.6 image stabilization lens. Even with a moderately wide aperture, the lens performs exceptionally well under low-light situations. I will eventually grow out of this lens, but for now it's doing well for me.

This site might help you out - http://www.digitalslr-camera.org/