When it comes time to connect your shiny new sound bar or AV receiver, your two main choices are HDMI or optical digital audio.

The simplest advice is to go with HDMI when you can. But if you can't it's not the end of the world.

Here are the pros and cons of each.

The basics
Both HDMI and optical pass digital audio from one device to another. Both are better than analog (the red and white cables). Both can pass multi-channel audio, like Dolby Digital. Both cables can be had pretty cheap.

The biggest difference is that HDMI can pass higher-resolution audio, including the formats found on Blu-ray: Dolby TrueHD and DTS HD Master Audio. These formats can't get transmitted across optical.

In terms of simplicity, HDMI also passes video signals. So if you want just a single cable between two devices, HDMI is your pick.