Good floor planner program?

I'm planning to have a house built. I want to draw up some sketches on the computer, so I am looking for a program that can help me do this. It doesn't have to be a professional architecture tool; in fact that would be too complicated just yet (but maybe later on, for the detailed work...?). A simpler tool would be better.

Features should include such things as ability to draw and move walls (not just using simple boxes), calculate room/floor area, add windows and doors, and the like. That's why Inkscape or OOo Presentation won't do. On Windows, a friend would just download a cracked professional architecture tool but that is not what I want to do.

Suggestions?

Solution 1:

Sweet Home 3D

Sweet Home 3D is a free interior design application that helps you place your furniture on a house 2D plan, with a 3D preview.

Solution 2:

I love Google SketchUp. It's not made specifically for this application, and I'm sure there are others, but if you're looking for simple, this is the ticket. And who can argue with gratis?

I guess Wine kind of sucks, though.

Solution 3:

It's not open source, not really a program, and the free version is limited, but I've found the flash-based floorplanner.com to be simple and a pleasure to use.