I think it helps to have a CRT monitor. Retrogaming is the main reason why I never switched to a TFT. Sometimes, people really look quite dazzled when they see my rig - as if they're staring at an anachronism.
You can make games look right in WinUAE. You just have to add a couple of resolutions to your graphics card - like to the custom resolution option of my nVidia.
Most games use 320x200 - just like DOS. A few 320x240 and some use half of PAL 360x288. It's easier if you double the resolution by using a filter and use separate configuration files for each game.