What is the difference between Canon T1i and Nikon d3100

I want to buy a dslr and I'm new to photography so I know nothing.
I went to best buy and they had a brand new D3100 for $ 549.00. After talking to the sales guy, he showed me a hidden open item (used) T1i. He said it was old and it was returned a long time ago but that it worked perfectly. I looked at it and it looked brand new! No scratches! And for $349.00 but he said the manager would drop the price cause he doesn't like holding open items. Anyway, which one should I get? I want the d3100 but it's so expensive! But the canon was nice too.

My pictures- I plan to take pictures of…
Building models (i'm an architecture student)
Houses
People
Landscapes
EVERYTHING lol

They are comparable cameras. Look at the link below for details.

Does the T1i have a lens? If so, then that's a pretty good price for it; about what a used one would sell for and if the one you've got is in mint condition and everything works, it's a deal.

If the T1i comes with an 18-55 kit lens, that's a good price. Buy it, if it comes with a warranty and if it has an 18-55.

The Rebel T3 and Nikon D3100 are currently Canon's and Nikon's least expensive new DSLRs.