By maxing out your 401(k)--in other words, by directing as much of your salary into your company-sponsored 401(k) retirement plan as your employer and the IRS allow--you win three ways.

In addition, many employers will match at least part of an employee's contributions. A recent Buck Consultants survey of 401(k) plan sponsors found that nearly 90% of plans nationwide now offer some form of a match, perhaps dollar for dollar or 50 cents on the dollar, up to a certain percentage of your contributions. And once it's in a 401(k), money is allowed to grow tax-deferred, with no taxes paid until it's pulled out, generally in retirement.

Here's where an (Roth) IRA enters the retirement savings equation. These accounts also allow you to achieve tax-advantaged compounding. However, most people won't be able to make any tax-deductible IRA contributions while they're participating in an employee retirement plan. The logical IRA consideration, then, will be a Roth (IRA), because money withdrawn from a Roth comes out tax-free, whereas money withdrawn from a traditional IRA will be taxed as normal income. You can contribute to a Roth--even if you're in a 401(k) plan--as long as your income is less than $100,000 if you're single or $160,000 if you're married and file jointly.