There are a number of options available, it really depends on what your budget is for NMS software.
If you are looking at low cost you could go with MRTG for just snmp performance related stats:
www.mrtg.org
If you would like to do more you could go with Cisco Works LMS which would provide:
Campus Manager -- topology map, user tracking, path analysis
Resource Manager -- inventory, config management, software image management
Device Fault Manager -- Notifications and polling
IPM -- round trip response, network performance and latency analysis
CiscoView -- graphical view of your devices
you could also consider other NMS applications such as NNM, but depends on what your budget and needs are
