If I really want a game I buy it and stop playing whatever I'm at. Like right now I bought Bioshock Infinite and stopped playing Jak III.
My backlog right now is:
1. Bioshock Infinite (started)
2. Jak III (started)
3. Trials Evolution (PC) (started, play it when I can't use the TV)
4. Sly 4 (started, playing on Vita, maybe I'll continue on PS3 after Bioshock)
5. Dead Island Complete Edition (bought it on PSN for 10$)
6. Okami HD (PSN+ next week)
7. The Cave (PSN+ next week)
8. Joe Danger 2 (PSN+, I'll play a couple of levels when my backlog is cleared)
I'll play this shit before buying any new games, which will be Ni No Kuni, Prototype 2, Grid 2 and finally The Last of Us, for which I'll drop ANYTHING I'll be playing when it comes out :D