I used a "tax professional" last year because I had some strange mil/airline stuff going on. After 8 (EIGHT) revisions due to my audits of his work, we finally got the returns submitted. As it turns out (and as usual) no one has your best interest in mind more than you. I went from owing $3,000 on his first iteration to getting a refund of almost $4,000. I vowed from then on that I'll continue to do my own taxes, this actually created more work for me doing it through him. This guy is a tax attorney and an airline pilot so I thought I had struck gold. Bright side of things is I have a very accurate template to use going forward. My best advice if you're going to do your own taxes is the same as what people said above, use TurboTax, use ProDiem or EZ Per Diem and if you buy and sell securities/bonds/funds/options in a taxable account use Gainkeeper.com. It's basically the EZ Per Diem of buying and selling stocks. If you stumble across a Expressjet Captain who is a tax attorney based out of Texas I highly recommend you steer clear!

That being said, once I start getting into rental properties/business accounting, I'll most likely hire a professional after some serious vetting.