ZaapIT - Mass Merge, auto merge, duplicates cleanup, bulk edit, bulk update, bulk delete , mass lead convert
ImportBuddy - It gives you a very easy solution to Add/Update CSV data into any standard or custom object of Salesforce without leaving Salesforce.com
Duplicate Check - Start creating data happiness. Find, merge and prevent duplicate records in your Salesforce Organization.
DataArchiva - The Next-Gen Data Management Platform for Salesforce
Apsona for Salesforce - Apsona for Salesforce is an add-on application for Salesforce to manage the data.
Cloudpond - Cloudpond is an AWS S3 storage connector utility for Salesforce.