I like to support the Indies by buying new because it encourages new games by new developers and I usually do if the premise of a game, the screenshots and the gameplay & reviews interest me enough that I feel I will get my money's worth in enjoyment, can afford it and I'm in a baagging stage. I would prefer to have complete new games when possible, especially when it's something I think I'd really like in my collection.
Buying new games from large publishers also helps to keep the genre alive and is important too.
The bottom line though has to be what a person considers a particular game to be worth and also whether that person can afford it. Personally, I will not buy a game at full price if I can't get enough hours of enjoyment from it. That means that those short games would never be played by me if I didn't buy them used. However, if I play one of those games I bought used and enjoy it, I will buy more games from that publisher.
While it's great to support the indie game developers and important, I think Carolyn hit it on the head when she said that producing a quality product will help the market grow. Once a company has a reputation for producing good games, they will sell many more. A new Indie without a reputation would do well to offer his or her games at a price a little below the usual game price and encourage sales for the first releases as some have done, so the buyers can sample his/her work without making a large investment.
Buyers on limited budgets deserve the opportunity to buy or sell used games so they can play more games. That's what a free market is all about. Since I rarely play games more than once, buying every game new would not be cost effective and not being able to buy them used or trade them for something I haven't played yet, would not make me buy more games new, it would just mean that I played fewer games.
It's great to be idealistic and always follow those ideals but the bottom line is that not everyone can afford to be altruistic and they should not feel that they can't look out for their own interests when buying games even though they comparison shop for other things.
Just my two cents.
Melanie