I used to use TurboTax.
Used TaxCut last year and liked it better.
I've also E-filed for the last 3 or 4 years.
It's awesome!
BTW: I work for accountants, and most of them say that unless someone has VERY complicated investment or income issues (inheritance, trust, own business) most people can and prolly should do their own taxes. Simple investments, single mortgage, and straightforward deductions is nothing more than gathering the records, and adding it all up.
BTW2: I do however, usually have one of the accountants just look my stuff over quickly to make sure I haven't obviously screwed something up.
BTW3: And if you are ever notified by the IRS that you are being auditing, hire a good accountant IMMEDIATELY! You wouldn't BELIEVE how much easier the process can be.
BTW4: BTW3 assumes of course, that you weren't trying to commit out and out fraud! :Q