When you start organizing your portfolio you will want to consider how you will be spending your money after you retire. Some money will be deposited directly into your checking account; such as Social Security where as other income could be less predictable. It is always nice to get extra income you are not counting on but you must not plan on this.
Variable annuities offer more choices than fixed or guaranteed annuities. Some of the things they offer that are not the same as a fixed annuity are, tax deferred earnings, a choice of payouts, plus the opportunity to make unlimited contributions if the annuity is nonqualified. The things that it offers different from the fixed annuity is that you have a potential for making more money and it also gives you more involvement on how to allocate your assets among your investments.