It's crunch time.

Hopefully, with less than two weeks left before April 15, you've at least started preparing your tax returns. If it looks like you'll be paying more tax than you'd like, making an IRA contribution can help you cut those taxes.

But with time running out to make an IRA contribution for the 2007 tax year, you'll need to get on the ball. Once you have your account open, you'll need to decide how to invest your cash. Here are a few tips for picking the best stocks for your new IRA.

Keep taxes in mind
If you want immediate tax savings, a traditional IRA is the right move for you; it will allow many taxpayers to take a tax deduction right now. In picking stocks for a traditional IRA, the most important thing to consider is that you won't have to pay tax on any income or capital gains until you start taking money out of your account when you retire.

In contrast, if you own a stock in a taxable account, you have to pay tax on your dividend income as you earn it. You can defer capital gains, however, as long as you hold onto your shares.

So to take maximum advantage of your traditional IRA, use it to buy stocks that pay the highest dividends. The following chart shows examples of how much you'll save each year if you invest $10,000 in a number of different stocks.

Stock

Current Dividend Yield

Annual Tax Savings

Pfizer (NYSE: PFE)

6.00%

$90

Vornado Realty (NYSE: VNO)

3.85%

$135

General Electric (NYSE: GE)

3.28%

$49

Microsoft (Nasdaq: MSFT)

1.52%

$23

Apple (Nasdaq: AAPL)

0.00%

$0

Assumes 35% ordinary income tax bracket and 15% maximum rate on qualified dividends.

As you can see, the higher the dividend, the greater the savings from owning your shares in an IRA. Furthermore, shares of real estate investment trusts (REITs) -- which generally don't qualify for the lower tax rate on certain dividends -- save you even more in an IRA. The same is true for fixed-income securities, like bonds.

How a Roth IRA changes things
On the other hand, if cutting your taxes right now isn't your primary consideration, a Roth IRA can be a better long-term bet. That's because rather than simply deferring your taxes until you take money out of your account, a Roth IRA lets you enjoy that growth tax-free.

That's a huge advantage over traditional IRAs, especially for growth stocks. In a traditional IRA, high-growth stocks like Intuitive Surgical (Nasdaq: ISRG) or Google (Nasdaq: GOOG) might make your account balance go up faster, but you'll pay tax at your ordinary rate when you retire and take out the money. You won't qualify for lower capital gains rates, even if you hold those shares for years.

With a Roth IRA, though, you'll never pay tax on income, whether it comes from dividends or capital gains. That gives Roth IRA owners a bit more flexibility in structuring their retirement portfolios.

Regardless of whether you pick a traditional or Roth IRA, make sure you don't miss the April 15 deadline if you haven't yet made your contribution for last year. What you'll save is too good to pass up.

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Fool contributor Dan Caplinger has most of his IRAs invested in mutual funds. He doesn't own shares of the companies discussed in this article. Microsoft and Pfizer are recommendations of Inside Value. Pfizer is also an Income Investor recommendation. Intuitive Surgical is a Rule Breakers pick. Apple is a Stock Advisor selection. The Fool's disclosure policy lays it all out for you.