I have the D3100 and it was my first foray into the world of DLSRs. I like it. It's basic, but has enough understandable versatility for a dilettante like myself and didn't cost an arm and a leg. My only complaint is that I occasionally have trouble with the battery, but I suspect that might be coming from neglectful charging practice from the user (cough cough). My brother and mother have Canon EOS Rebels and they like theirs too. My brother takes pics of his kids and my Mom likes to take pictures of her garden and the birds that visit it. I find that they are a bit light-- it's purely emotional, but I like a bit of heft to my camera.
I chose Nikon because it has something called "D Lighting". This means that even if an item is backlit and dark in the foreground won't lose detail and can be enhanced later in the editiing process, if you want. That's only very recently become important to me, despite my buying the camera years ago.
I use it for landscape photos primarily and use the kit lens. Otherwise, I agree with PastryGoddess in talking to a person in a camera store-- I found that they ask complicated questions, but they dumbed things down enough that eventually I figured out what I liked and wanted. I also only use the built-in flash, when I use a flash, which I find I rarely have to do because the light sensors are so good.