Hi d_golly.
It seems the guys who have answered your question don't believe in cables making a difference, either that or they have read to many cable arguments in forums. I say differently. But you should go to a dealer and listen for yourself as in my opinion they can make or break an audio system. It's all to do with shielding on the cables and how well they keep out interference. I have been upgrading the cables, Interconnects both digital and analogue and the mains cables. I confess to only having a relatively cheap speaker cable by Cambridge Audio on my Hi-Fi but its holding up ok for now but the rest of the upgrades have made a huge audible difference.
Most of the harshness has gone, there is audibly more headroom and the bass is tighter and more defined.
From your source to your DAC I recomend a Chord Company Prodac £40-£50 with the VEE3 plugs on the end. You want the least amount of metal on the terminations of each cable.
For the analogue connection a Chord Chameleon with VEE3 plugs will do you well for about £120/m and speaker cable. Yes a heavy gage cable will work better and a shielded heavy gage cable will be better still. For your mains cable I suggest Isotek Premium. You may think why spend £80 or more on a mains cable but until you go and have a listen to the difference they make you won't know.
As I said. Only you can make up your mind. All of us have different views and can hear/not hear different things so only your ears will give you the answer to which cables are best.
Good luck and have fun listening at the shop. Feel free to take your source (DMP-BDT500) to the shop if they don't have one so you here the cables on your own system. They may even lend you some for a small fee that should get refunded once you take the cables back.
The Cable Madman.