Scaler set to none

scaler=none
output=openglnb

(Output doesn't depend on you're personal taste, but does depend on what OS you currently use. opengl should be supported across platforms)

scaler=none
output=opengl

(Output doesn't depend on you're personal taste, but does depend on what OS you currently use. opengl should be supported across platforms)

,

I'd say that output=openglnb is closer to MS-DOS, as the normal opengl output enables bilinear filtering that smooths stuff a bit. But well. Try both and see what floats your boat.

output=openglnb results in rows and columns of pixels with uneven sizes (some are thicker than others). At least if you use aspect=true to preserve the original aspect ratio.
CRT monitors didn't produce prefectly "sharp" scanlines anyway, depending on resolution and dot pitch. So the slight blending caused by bilinear filtering isn't a big problem for me.

But it all depends on your monitor (type, resolution, aspect ratio) and on the emulated graphics modes.

These are the settings I use:

fullscreen=true
fullresolution=0x0
output=openglnb
aspect=true
scaler=normal3x

I use three settings:

First, the widescreen approach:

fullresolution=1280x800, 1600x1000, 1920x1200
output=openglnb
aspect=false
scaler=none

That will get you rows and columns of evenly sized pixels, every time.

Second, the proper aspect ratio approach :

fullresolution=1600x1200
output=direct3d
aspect=false
scaler=none

This will give you a proper aspect ratio for 320x200 games and evenly sized pixels, but text modes may not look quite right.

Third, the CRT approach:

fullresolution=original
output=surface
aspect=false
scaler=normal2x

With these settings, the game will look as it should on a VGA monitor. But it requires a CRT.