I'm a big supporter of Xbox Live Arcade and Steam...my wallet is a testament to this.  But the one thing that has really caused me to increase the amount of money I spend was when they both started having weekly sales.

The Steam sales over 4th of July weekend made me think about this quite a bit because I spent way more money than I normally would and it happened very quickly.  The constant daily deals had me checking steam every day at noon to see what was new.

Before the sales, I always knew the game would be there...so why buy it now?  When I'm ready to actually begin playing I can just get it right then.  I find when a game I'm even remotely interested in goes on sale that my thinking then switches to "I know I'll play it eventually, so why not get it cheaper?"

So, now I generally wait a while to see if a game I'm interested in will go on sale if i'm in no hurry.  There are exceptions to that, like Monkey Island 2: SE that I immediately logged onto Xbox live to purchase it.  Maybe there is hope that all games can go digital on release and we can bypass the expensive retail avenue to make games cheaper for everyone.