Physical media - b/c that's mostly all done for me. That way, if there's patches out there - well, you can just use patches and stuff those on a small CD or DVD.
Provided the game doesn't have a zillion patches that need to be done in order and installs need to be done in order for expansions, DLC's, etc - I'm looking at you, NWN2 here....and I bought it on GOG so I could just to the big install of the game w/ all its expansions and DLC's/expansions altogether in one big & easy clip.
Problem is - with so many games using closed systems and not tossing patches on places Fileshack, it's almost now a waste to do that b/c your game-client app likely will update the game in full...and you basically will have to back-up the entire game.
With modern games though - well, sometimes these games can be huge and don't fit on CD's, DVD's, BR's and there really isn't a media format here on PC. Often, I just back 'em up on say external HDD's.
EDIT - I do like GOG's approach for digital with BIN files and EXE's though, especially if it's in its most patched-up state right there.
Post edited 2 days ago by MysterD