Whichever DigiCam you buy, don't take anything below 5MP. IMHO, the resolution can give you better printouts of little bigger size. If its not within budget, wait for some time. You don't buy DigiCams every now and then. Alternatively, since you are a casual photographer, look for an older model e.g. Nikon Coolpix 5200. 5900 is the current one.
As for brands, Nikon rules! However, Sony and Canon are not too far behind.