Hullo everyone!
I'm not a "new" user to this forum; I have browsed here a year or two ago and [recently?] decided to make an account. I enjoy stop motion animation (when I get the time, with studies and whatnot). Until now, I've been lurking in the shadows of this great website. I love using DSLRs, so this time I just had to give some input. I have used the compact Sony NEX-5, but I am now using the Sony a55, an amazing camera. I plan to upgrade soon to the 24-megapixel a77. I used to always be a Canon person; and I'm sure Nikon is great as well. But somehow, with the mainstream consumers, Sony just barely hits the mark at one of the top-rated SLR brands. Of course, there are other great brands such as Pentax and Fujifilm, but none has the great price-per-features ratio as Sony IMO. Take it with a grain of salt, but you can buy the Sony a55 (or updated a57) for about the same price, or cheaper than a Canon Rebel T2i or T3i. Alas, I am not educated as well with Nikon , but I would recommend considering a Sony DSLR for your next purchase. The a57 can record in 1080p @ 60fps as well as 24fps. Award-winning filmmakers such as James Cameron (creator of Avatar & others) are beginning to film movies not only in 24fps, but also in 60fps since apparently that is what the eye sees and it appears more realistic and fluid. If I'm not mistaken, the upcoming movie The Hobbit has been filmed in 48fps. Yes, the Sony a57 has a 16-megapixel sensor as compared to the classic entry-level SLRS by Canon, which are typically at 18 megapixels. In truth, megapixels DO NOT MATTER unless you are expanding the picture to be displayed in a large frame, or even a billboard. Then, of course, the pixels matter as you stretch the image. Yes, obviously an 18-MP sensor wins over a 10MP sensor, but when you compare 16 to 18 you really can only tell the difference by pixel-peeping.
Please do read this when you get the chance:
http://www.kenrockwell.com/tech/mpmyth.htm
I would expand on the many features of Sony DSLRs, but I feel like I'm not giving the other brands a chance. Honestly, the above information may not matter to the average consumer, but you should research your camera before you make the final decision to buy it. Also, about the EOS Rebel line: If you must, buy the T2i, not the T3i. The T3i is almost EXACTLY THE SAME as its predecessor; all Canon changed was, if the reviews were correct, part of the design and they slapped on a flip out screen, then charged $100 more for it. Look up "perceived obsolescence." (http://www.mymoneyblog.com/planned-vs-p
cence.html)
If it matters to you, for the extra 2 megapixels (over the a55 and a57) then by all means get the Rebel camera, but do not get the T3i unless you feel like spending more money on a flip-out screen. All this information is more based on your use of the camera for a general-purpose DSLR rather than the best camera for animation. I know Canon EOS cameras have great Live support and connectivity for stop-motion programs.
With all due respect, the kit lens is a terrible choice to stick with unless you are on a tight budget. Try to get one very good lens, even if it is slightly expensive. (You'll find that the good lenses are always more expensive. Keep in mind, with cameras, the phrase "You get what you pay for" is all too true). I would recommend either a 24mm, 35mm, or even 50mm lens with up to 1.4 or 1.8 apertures. These prime lenses have good reviews across all camera brands. Recommended zoom lenses would be the Sigma 24-70mm f/2.8 (yes, pricey, but this works across many different brands and the fixed aperture, even at a large zoom, is a plus); Canon EF 28mm f/2.8 (relatively cheap, good reviews); and the Sigma 10-20mm f/4-5.6 (very wide angle). You may be able to attach a macro filter to the lenses if required. You really do not need a large zoom or telephoto lens for stop-motion animation, which is why I recommend these short-range lenses. Do get a lens hood if you can, they will reduce vignetting from the light and have other benefits that I forget right now.
On a last, random note, megapixels will not matter when brickfilming; rather, the video quality does. (facepalm) Sony, Nikon, Canon, and all other brands are great, all you need to do is research what you think is best for your preferences.