I somehow missed this thread so I'm coming in late...
I think it really depends on the story... If you show us the Marine in a total life decline, you may want to start him off with some decent stuff and then... As he spirals downward, show us how he will drink any fucking thing he can get his hands on.
In other words...
He starts out with Chivas or Johnnie Walker... Even Jack. He drinks only bottled beer in the beginning... The more expensive brew pub stuff...
Maybe he even scoffs at those who drink cheaper beer and whiskey as if he's some kind of connoisseur.
As he spends more money... Maybe loses a job... Loses a relationship... (you get the idea), he succumbs to the fact that all he wants is a drink.
He could even steal a bottle of Thunderbird from a wino...
"WHAT'S THE PRICE? A QUARTER TWICE!"
Show us his decline visually by having him reach for crappier and crappier alcohol...
If this is a tragedy, he could even end up drinking something like rubbing alcohol...
Show us his decline THROUGH his choice of drink... We'll get it. And, you don't really need the brand names... You just need to make the places he gets his liquor part of the downward spiral...
Maybe he goes to a crowded bar and steals drinks from people's tables.
Maybe he buys some teenagers some booze and KEEPS it.
Maybe while acting like he's shopping in a grocery store, this is simply a cover for him to open beer and whiskey and drink...
I could go on and on but I think you get the idea...
Good luck with it!
filmy