Demand for Salesforce certified professionals is increasing everyday and getting yourself certified by Salesforce proves your indepth knowledge and hands on experience in Salesforce.
Salesforce Administrator:
Administration Essentials for New Admins (ADM201)
Administration Essentials for Experienced Admin (ADM-211)
Salesforce Developer:
Building Applications with Force.com and Visualforce (DEV401)
Apex and Visualforce Controllers (DEV501)