There's not much of a difference, the Canon is slightly better for filming the Nikon has slightly better controls. The biggest difference is the structure of the menu system, which you like better is up to you, i prefer the Canon menu structure.
The most important thing on the camera is the lens. The lens makes the image, the camera body just records it. The reason you buy a DSLR is because you wan to use multiple lenses. So go ahead choose which lenses you want and then buy a camera body that fits your choice of lenses.
to choose which lenses you need/want, i suggest you read lens reviews on sites like these:
http://www.cameralabs.com
http://www.photozone.de/
http://www.dpreview.com/
if you don't understand what: focal-length, aperture, exposure & crop-factor means type these words into youtube and watch a few videos about it before you buy anything.
One final tip, all the people that do lens-reviews are impossible to please, so if they write that a lens has average sharpness or image quality that translates to really nice pictures for normal people.
But take all of this into account, but if you have a hard time understanding the basics, id advise you to learn first, im not to sure about the Nikon, but the T3 has absolute crap video due to it all being auto, unless you install something like Magic lantern that is.
I have used both (I have the nikon my mom has the cannon) and i do prefer my nikon over here cannon, however this may be because I've baught some lens for mine and she is still using her stock lens. (Highly recomend you spend a couple bucks when you can on lens)
Check dxomark.com for in-depth technical reviews, then go to a store and feel both of them, how they feel in your hand and where the controls are, then decide, and you'll be happy.
200 dollars budget for lenses, that's difficult, but doable
get the camera with the 17-55mm kit-lens,
low-light: get a cheap 50mm F1.8 from either Nikon or Canon
macro: get a reverse macro ring -> allows you to mount your kit-lens back to front turning it into a powerful but all manual macro, http://www.youtube.com/watch?v=uVYtgJi2rLc
"long range scenery" ? not quite sure what that means, i guess you mean tele-zoom lenses like 50-200mm or 70-300, those usually start a 200 to 300 dollars (so you might have to save up a bit for this)
I urge you to read allot of tutorials,
also digital photography makes it possible to improving the image on the computer:
gimp is a free and very powerful software for post-processing an image, there also is adobe photoshop, which is very expensive (it is easy to pirate it but be warned: illegal copies of photoshop sometimes contain viruses)
some other things you might like to acquire/research later on:
The 50mm 1.8 is a must have. Both DSLR's will do the job, what you're really picking is what brand you're going to be committed too. I personally prefer Canon over Nikon but in all reality it doesn't matter what you go with, don't let anyone tell you otherwise.
When I was getting into photography, back when I had my old digital rebel, I use the 50mm with extension tubes for macro. For example.. https://secure.flickr.com/photos/saintseminole/290981505/ (Not my image)
The 1100D is Horrid at video and is a giant stepdown from the t3i id Much more reccomend a t2i or t3i you can find those for aroun 550-650$. Just look for cheap ones! I prefer canons and i have a Canon t4i (650D)