1. buy only games you really want,
2. buy only games below 15-20$(if you want to buy game for multiplayer like Halo or Modern Warfare that's a different story though),
3. make a list of games you really want to play(must haves),
4. spend only certain amount of money/month on games,
5. if there is for example 10 modern war multiplayer shooters on the marked don't buy every title, but only the best one that have huge online community and will keep you occupied for a while. besides you don't need 5 online shooters cause you will probably play maybe 2 of them at a time,
6. atleast play and finish most of the games you have before buying new ones,

simple, but it works for me.

I don't buy a new game until I am finished with the one I am currently playing. This helps me not only save money but I don't rush through new ones nearly as fast. This also prevents the fables "backlog". IMO this is the best method. All the games in my collection I have played through to the finish with very few exceptions.

Welcome to the club. I buy stuff I really want (which is a lot as I have a broad liking of many genres), but then I buy a ton of stuff at $20 or below. In the last few weeks I've picked up older titles.

Ah, the dilemma of the collector. I mainly buy used games and games that are likely to go OOP rather quickly right now, yet my backlog continues to grow at an alarming rate. And yes, I've not started many of my games, but that is because most get played until I either finish it or tire of it. After Years keeps the Wii busy, Tsugunai on PS2, SMT:DS on the DS (with a smattering of FE:SD), and I've started Yggdra Union on PSP.

I keep a list of games I want on Amazon.com. 360/Wii games I buy once they're below $30 and DS games I catch for $20-$25. I'm not the type of gamer that has to buy games within first week of release. I'll get to all the games eventually. It keeps me sane and I usually only play one game per system until I beat it before I start another one.