Deleting your Google Account will affect all products associated with that account (i.e., Blogger, AdSense, Gmail), and affect each product differently. Before deleting your Google Account, review the data associated with your account on the Google Dashboard. If you use Gmail with your account, you’ll no longer be able to access that email. You’ll also be unable to reuse your Gmail username.

Read up on specific information about other products that you’re using.

To delete your Google Account:

1 Sign in on the Google Accounts homepage. (If you forgot your password, you can reset it).

2 Click Close account and delete all services and info associated with it to delete your account. If you don’t see this link near the bottom of the page, your account was likely created through an organization or company.

3 Confirm your account deletion. To do so, you’ll need to select these two options:
“Yes, I want to delete my account,” and “Yes, I acknowledge that I am still responsible for any charges incurred due to any pending financial transactions.” (You can safely select the latter option if you haven’t used any of Google’s paid products, such as AdWords and Google Checkout, or if you have no pending financial transactions related to these products.)

Source : Google help