Ah yes, Nortel configuration mangler -the bad ole' days, LOL..
I think that you'll be pleasantly surprised with the size-appropriate assortment of Cisco network management tools available. There are many 'small installation' tools and I'll let someone else speak to those as my last 10 years has been primarily involved with the enterprise tool sets..
AAA - Typically you'd start by comitting to a centralized Authentication, Authorization and Accounting infrastructure which you'll use to control access to all infrastructure devices via. The toolset that we use here is CiscoSecure ACS. It comes as an appliance or as software. We run it in a Windows 2003 VM at 2 geo-separated locations. It can be as simple or as complex as you wish to make your access control. Protocols supported include TACACS (recommended for routers / switches) and RADIUS (for non-cisco devices and 802.1x authentication needs).
Routing & Switching - In the R&S space, your main enterprise go-to tool set is the CiscoWorks suite. This has several different components for configuration management, change release / mgt, configuration repository, code (IOS) repository, code upgrades, etc. It also has some components for doing monitoring (up / down, syslog processing, etc)
Wireless - In an Enterprise network, we typically migrate the APs from autonymous configuration to an LWAPP / CAPWAPP controller-based system. The toolset for managing this is Cisco's "Wireless Controll System, or WCS". It provides significant ease of management and monitoring and can scale to support thousands of APs / many controllers. This controller-based wireless infrastructure has been an absolute god-send. There's just no way that we could have grown the wireless infrastructure across all of our hospitals without it (and still maintained head-count).
VOIP - Cisco's enterprise voice toolset is a combined package of Cisco Unified Operations Manager, Service Monitor and Provisioning Manager. The tool takes seeding from the CiscoWorks device data base and as a result, is able to depict a fairly wholistic view of your entire VOIP infrastructure from Call Manager all the way to closet switch to phone. The provisioning manager provides a template-driven rule-based experience for provisioning phones and other services so that your MAC work costs can be reduced and also have a more 'uniform' result.
These are all 'enterprise' class tool sets. Cisco also has other tool sets that may meet the needs of smaller installations. I will say that in 2000, my first real experience with CiscoWorks made me wonder if nortel's Configuration Mangler was really so bad after all. BUT Cisco has had 10 years to work on it and has consistently improved the interface, performance and stability of the product all while continuing to significantly increase functionality.
Hope this helps.
Bill Strutton
Architect, Data & Voice
Trinity Information Services