Since a majority of Small Business owners usually use QuickBooks Pro, I thought I would let you know where you can get the cheapest price.  Sam's Club currently has QuickBooks Pro 2008 for $149.88.  I originally bought my 2006 version there, and am about to upgrade due to the better compatibility with Windows Vista.  And unfortunately, while I would use Microsoft's account program (since I get it for free through the Microsoft Partner Program), my accountant only works with QuickBooks (as well as much more expensive packages).

Make sure to search for QuickBooks rebates, however  they aren't always available.

Sam's Club - Intuit QuickBooks Pro 2008: $149.88