DSLR's these days are pretty much all very, very good cameras. Things to consider:
[Ergonomics]
You should really physically try them out and see which one feels comfortable in your hands. How are the controls layed out, and are the functions you need easy to reach?
[Access to advice / lenses]
Do you have relatives or friends that are experienced with DSLRs? do they have lenses that you can share? As an example, a friend is going Nikon because his brother already has a Nikon DSLR and a few zoom lenses while he gets primes...
Since you are new to DSLR, you may not know what you exactly want. Try not to get stuck on what brand yet. Instead, pick up a DSLR, read up on photography and go out and shoot. Once you become more experienced at shooting a DSLR, you will appreciate features that the camera has or notice things that is lacking. Since these are i'm guessing body plus kit lens, it's not too much to switch between nikon or canon. That being said, if you can afford it the better body is just better (ie. 450 > 1000, espcially since the price is pretty close).
Another friend is in the same position as you and he's trying out all the brands, olympus, sony, canon, nikon, but he's lucky enough that his work has all these DSLRs for him to take home and try.
Hope this helps.