Ultimately the resolution you use doesn't really matter. Unless that is, your computer/video card is so slow that it simply can't handle higher resolution without noticeable slowdown. I personally use 1280x1024x16 because I've noted that using 32-bit color can cause more slowdown in framebuffer-heavy scenes. If you use resolutions that are not 4:3, then you might want to force ePSXe to keep the original ratio (or not, if you don't might subtle distortion). If you are a purist, you'd naturally want use P.e.O.p.s software plugin, otherwise, if your video card and computer can handle it, use Pete's OpenGL2 plugin. For sound, SPU Eternal 1.50 beta 2 is probably the best. The rest of the plugins don't really matter.