It all depends on what you are looking for, and how much you are willing to pay.

Here are a few top contenders:

UltraTax:  Generally considered better software, but definitely higher priced and is worksheet-based, so there will be a steep learning curve.  Made by a company focusing on tax preparers, rather than consumer do-it-yourself software.

Drake:  Superior customer support, lower cost and many people think it is the best thing ever.  However, it is less automated and definitely more 'clunky'.  It is mostly worksheet based (which means a steep learning curve).  Made by a company focusing on tax preparers, rather than consumer do-it-yourself software.

ATX:  Lower cost and similar entry as ProSeries.  Less automated and a bit more time consuming to enter data.  Made by a company focusing on tax preparers, rather than consumer do-it-yourself software.

TaxAct Professional:  Lower cost and VERY similar entry to ProSeries, so the learning curve will be fairly small.  However, less automated and made by a company focusing on do-it-yourself software.

There are others brands of software, but these are the one that most people consider.