Originally Posted by Photon
And this leaves you with two choices, I guess. If you want to stick with 1:1 pixel aspect, you will have black on left and right border for PAL games, and black on top and bottom border if you play NTSC games. (Or borders all around, if you play "320x200-in-320x256-resolution" games.) There's no other way to display the whole picture and still have 1:1 pixel aspect.
Unless you have a 16:10 widescreen display: because then you can fit the displayed area of 320x200 pixels perfectly filling the entire display while keeping 1:1 pixel aspect ratio (since 320x200 is 16:10-format if the pixels are square).
Ideally would then be a 16:10-display which is a multiple of 320x200 (so you don't have to scale) like 640x400, 960x600 or 1280x800 (=> native resolution of many notebooks).