While we’re all catching our collective breath after filing our 2008 federal and state tax returns … it’s a good time to consider the most recent findings on Americans’ tax preparation behaviors.

You might expect that a significant portion of tax filers are now using “cheap ‘n easy” computer software programs like TurboTax to complete and file their tax forms.

Well … not so fast. A just-released survey conducted by Mediamark Research & Intelligence finds that only about 20% of U.S. tax filers used software programs. Another ~13% prepared their own returns the traditional way — by hand.

But fully half of respondents relied on outside professional help from a CPA, tax preparer or national chain resource like H&R Block — despite the fact that such services cost much, much more.

Why would half of all adults who file personal federal taxes feel the need to pay a lot more for professional assistance rather than take advantage of affordable software programs? There are a number of reasons: the complexity of the federal tax code … intimidating tax forms and instructions … concern about the safety and security of computerized software programs and electronic filing … and, not least, fear of retribution from the IRS for making an error.

The fact that many of the tax returns completed by professional preparers still contain errors doesn’t seem to make much difference. Many taxpayers would rather shift the responsibility of “filling out and filing” to somebody — anybody — else.