If the interior doors on your house are the flat hollow core version like this, but you prefer the raised panel look, well, here's a way to have this without going to the trouble and expense of replacing the doors.
Almost any flat door can be made to look like a panel door by applying moldings to the face. Now before you actually start attaching these down, take a little masking tape and do some experimenting on placement. Once you've come up with a design and layout that you like, then take a straight edge, draw some lines and then you can remove the tape.
We've got our lines drawn on the face of the door and I've gone ahead and cut some pieces of molding and put 45 degree angles or miters on each end. I used a power miter saw like this one right here, to do it. It makes it very, very fast. You can buy or rent these or you can use a hand miter box, like this one.
Now, the next step couldn't be easier. We're going to take some glue, put it on the back of the molding like this, and then we're just going to stick this on the door. We're going to put the back edge of the molding right here along the line that we drew earlier. Kind of move it around a little bit, kind of squish the glue out. And then I'll just take three more and make a complete rectangle out of this.
After a little stain and varnish or a paint if you prefer, you've got a plain door that looks like a million bucks.