Generally the advice will be get a Cannon or a Nikon, but there are some decent entry level camera's by other manufacturers such as the Sony A200.

In reality, you wont go far wrong with any of those camera's, they'll all produce images that will satisfy you once you work out how to use them but personally i'd go with the Nikon as i just like the way my D60 feels to hold and use which is basically the same as the D40.