Xbox Live Rewards are in full effect, meaning your Gamerscore entitles you to certain discounts on Xbox Live goodies.
For example, a GS between 3,000 and 9,999 gives you a gift on your birthday (something awesome as this range is equivalent to less than one dollar). Between 10,000 and 24,999 gives you a one percent rebate for the month, and over 25,000 gets you a whoppin' two percent.
Being that time is money, and unlocking Achievements takes time, I'm still not sure if it's worth it. I'm in the middle of doing that math. Results in soon.