While certainly there is no one-size-fit-all, when it comes to 401(k) vs Roth IRA question, the best advice is almost always to take advantage of the full employer match first (free money!), then to make full contribution to Roth IRA, before contributing to non-matched 401(k) limits.

Generally, it's best to invest in a 401(k) up to the employer's match -- otherwise you'd be passing up free money. But if your employer doesn't offer a matching contribution, go with a Roth IRA first.

You can invest up to $4,000 in a Roth IRA this year. If you want to save more, you can contribute to your 401(k) after you fully fund your Roth. You contribute after-tax dollars to a Roth, so it won't reduce your taxable income like 401(k) contributions will, but you can withdraw the earnings tax-free once you turn 59½.

This is important if you expect to be in a higher tax bracket when you retire. And there are other benefits with a Roth that you won't get in your 401(k), such as no mandatory withdrawals and no penalties if you need to withdraw your principal early (for more, see An IRA Owner's Manual).

If you make too much money to qualify for Roth contributions ($110,000 for singles or $160,000 for joint filers), max out your 401(k) first, then invest in a traditional IRA.

But before you invest in any retirement plan, make sure you have three to six months worth of living expenses saved in an emergency fund, and you've paid off your high-interest debt.