I prefer renting single player games like Assasins creed because i can beat it in a few hours and not play it ever again. I buy multiplayer games though.
Since Gamefly is pretty much the Netflix of videogames, I'm going with renting since you can play it as long as you want and send it back when you're done.
I will say it depends on the game I thinking to buy. When it was a game that I knew was really good then i will buy it and not rent but when I don't know much then I will rent it.
I don't do either. The whole concept of paying for a game is just stupid to me.
If I'm desperate to play a game, which happens once in a blue moon or two, I'll just pay a visit to some online game site (sometimes this one) and play a flash game or two. It's free. Why should I go out and buy a console and then buy or rent more games for it if I can just play free ones on my PC for no cost at all?
I can't say I understand the logic of the younger generations.
I buy games that I know I will have a long time which are usually the ones that have a good multiplayer such as Call of Duty for an example. I usually don't rent games at all.