There are a number of options available, it depends on the total number of devices you have and your budget.
SNMS is a Cisco product that can manage up to 50 devices and you can do some of the functionality of CiscoWorks LMS (mentioned below)
If you want to do more security related functions with the PIX you might want to consider VMS.
Most users seem to use Cisco Works LMS as their Cisco product when managing Cisco equipment. This software provides:
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