Which DSLR camera should I buy?

I’m a beginner who isn’t very well versed in Digital SLR cameras, but I need to get one for a class, and for personal needs. I need one that can take photos of paintings and drawings but I also need one that can take outdoor photos, such as nature and wildlife. So far, I seemed to have found some good beginner cameras on bestbuy and amazon.com for 450ish. They are a Sony Alpha, NikonD3000, and a Canon Rebel XS. The Nikon and cannon are 18–55mm f, but I have no idea what that means! I think I am leaning towards the Nikon more, but I am having a hard time making a choice. I have heard that they are all relatively equal in performance and quality, so it is basically at this point opinionated on which one I want. Thing is, I just can’t make a choice because I am afraid of making a bad one!

Can anyone with experience in these cameras give me some info and advice?

links to the cameras:
http://www.amazon.com/Canon-XS-Digital-18-55mm-Black/dp/B001CBKJGG

http://www.amazon.com/Nikon-D3000-Digital-18-55mm-3-5-5-6G/dp/B002JCSV5I/ref=sr_1_1?ie=UTF8&s=photo&qid=1263353970&sr=1-1

(copy n paste this one)> http://www.bestbuy.com/site/Sony++Alpha+10.2-Megapixel+Digital+SLR+Camera++Black/9342473.p?id=1218087881931&skuId=9342473