Let me add my recommendation for FreeTaxUSA.com. I am a newly married grad student on fellowship, which implies juggling estimated taxes, confusing withholding rules, scholarship income, a name change, and first-time joint filing. Needless to say, I am not a "simple" case. After TurboTax failed to prepare my forms correctly (!) and wanted to charge me for the displeasure, I went looking for an alternative. FreeTaxUSA.com is where I landed.

The interface is fairly minimal. The workflow mirrors the questions/boxes on the IRS forms/instructions, a very helpful feature in my situation since I could easily cross-reference the relevant IRS publications when necessary. They provide excerpts from the documents as you go, which is all I needed in many instances. Unlike TurboTax, the prepared forms were actually correct (to the best of my knowledge, I am not a tax lawyer).

Simple, cheap, reliable. Would and do recommend.

EDIT: Story is related to last year, I plan to use them again this year.