How much do you plan to spend?
Do you want an SLR or a Point and Shoot?
An SLR is going to take better pictures, but if you are only going to own one camera, you may want something a little easier to take with you while still getting decent pictures.
It's easy to just name a high dollar camera and say “thats the best one,” but if it is out of your price range; what good is that opinion going to be to you….?
With that said….
Canon or Nikon would be my first two choices. I have a Canon 20D that I've been using for several years. It's no longer available new, but can be found at a reasonable cost used. I have three different lenses for it, so I can get most any shot, and with the Canon 580EX flash I get great results even in poor lighting conditions.
Though I have never owned Nikon, I have used a Nikon D200, and was very pleased with it, it's a nice camera. As seen here:
http://www.nikonusa.com/Find-Your-Nikon/Product/Digital-SLR/25235/D200.html
The description includes “Durable, magnesium alloy body,” so it seems since the lower end models from Nikon make no mention of what the body is made of, they make “cheap plastic” cameras as well. My 20D, and several other Canon models are also made of magnesium, and some models are plastic. Both Nikon and Canon do that, it gives the consumer a lower cost option in their camera line. If you can spend the extra $$ to get the better one, go for it.