There are a number of good packages out there.  SAS is my personal preference.  It has a wide range of data management tools, and you can document all edits and created variables in the code for future reference.  

"Best" is relative and depends largely on what your requirements are in terms of resources, study data and your data collection method. Have a look at REDCap and Epi Info for data entry and validation. They both contain some basic functionality for data cleaning.

www.project-redcap.org

http://wwwn.cdc.gov/epiinfo/7/

epi info is free and has backup help