http://rewards.xbox.com/myachievements/
As part of the Xbox Live Rewards program, Microft has just added a "MyAchievements" feature. There are three reward tiers based upon your Gamerscore and require you to have an XBL Gold Membership:
| Gamerscore | Reward |
|---|---|
| 3000-9999 G | A Special Gift during your birthday month |
| 9999-24999 G | A Special Gift during your birthday month and a 1% Rebate on your Xbox LIVE Marketplace purchases each month |
| 25000+ G | A "Special Gift" during your birthday month and a 2% Rebate on your Xbox LIVE Marketplace purchases each month |
According to the terms and conditions - the "Special Gift" has a retail value of $0.25 - so it wont be anything special (i.e. a t-shirt for your avatar or something). The 1% or 2% is not huge either - but it costs you nothing and is better than a kick in the teeth. Also make sure to be completing the survey each month for a free 20G. Game on! :)