[adogand6kids]

It depends on which audio signals you are passing. If you own a high definition player capable of decoding and passing high resolution audio from BD or HDDVD then definitely you want to use HDMI. The lossless audio codecs (Dolby TruHD etc.) carry much higher resolution audio signals and cannot pass over coaxial or optical digital cables. Also, if your player allows decoding of DVD audio discs or SACD's then HDMI (depending on the version) will allow you to pass that info to your pre-pro/receiver. Coax or optical digital cables cannot pass this information. It used to require having RCA pre-outs on your DVD/SACD player and connecting them to your pre-pro/receiver. This will save you from having to connect 5 sets of RCA cables from your player to your pre-pro/receiver. If you are just wanting to play the standard Dolby/DTS soundtrack on a DVD, or music from a standard CD, then the only advantage of HDMI over coax or optical is saving one cable.