Should I buy a CD/SA-CD player, a CD/SA-CD/DVD-Video player or a ‘universal’ CD/SA-CD/DVD-Audio/DVD-Video player?

That’s a matter of preference. Advantages of ‘universal’ players obviously include compatibility with more media using fewer devices but as a drawback you may feel the video circuitry distorts the audio. Even if the device offers the possibility to disable the video circuits you may still feel it’s surely a compromise. In that case, or when you don’t object to having multiple devices for your various media, or if you listen to music and watch movies in different rooms, a dedicated CD/SA-CD audio player may be your best choice. Otherwise you’ll probably find the combined player more convenient.  more