There is no visa for someone who wants to come to the U.S. to retire.
If you want to spend some time in the U.S. as a retiree, you should apply for a longer term visitor visa (B-2) from within your home country. You will be required to leave the U.S. after the visa expires. Financial independence and international travel health insurance from your home country is highly recommended as you will not qualify for any benefits in the U.S.
Another option is entering the U.S. with an investor visa (EB-5) which requires investing in a new business venture and providing proof of the capital as well as satisfying a few other requirements (i.e. number of employees, etc.). http://www.uscis.gov/portal/site/uscis/menuitem.eb1d4c2a3e5b9ac89243c6a7543f6d1a/?vgnextchannel=facb83453d4a3210VgnVCM100000b92ca60aRCRD&vgnextoid=facb83453d4a3210VgnVCM100000b92ca60aRCRD
You can also play in the Green Card lottery at http://www.usagreencardlottery.org.
There are people who support a ‘Silver Visa’ for retirees who want to live in the U.S. but it is not officially considered by Congress yet.
For more information on other visas, please visit the website of the U.S. Citizenship and Immigration Services at http://www.uscis.gov/portal/site/uscis