I'm missing out on a ton of good games, because I can't rent them anywhere. I'm sure there would be certain games I would try via rental, and then feel compelled to try to buy it right away.
However, I only have so much free time, and end up with too many unplayed games, that I try to be picky and only buy a few games here and there. So I understand the concept of missing out on games. You can't get all of them, and even if you could, you wouldn't have time to play them all, there isn't enough hours in the day.
Having said that, there are tons of games I would love to "sample", if only I could rent them locally in a convenient manner. I can't wait till Redbox gets with the program.