Advice on Camera Upgrade Please :O)

I’m looking to buy my first DSLR camera. I’m just a beginner living in paradise with so many photographic opportunities that I’d like to have a better camera (currently I own a Canon point and shoot) to take advantage of them. I found some on my local Craigslist and was hoping some of you might take a look at this initial list and see what you think. Any feedback or advice? Maybe a recommendation of something not on the list?

Thank you for any input you are willing to spare. Pics are below this list. If you mouse over the pic you will see the identification.

1. Nikon D3100 with 80-55 Kit lens: $500 (no link)
2. Nikon D5000 w/18-55 and  55-200mm Nikon VR lenses: $700
3. Canon XTi w/EF-S 18-55mm lens: $475
4. Canon T1i w/ 28080 lens UV filter and 22-55 lens: $500
5. Canon Rebel EOS XTi 400D Sigma 18-200 lens: $325