I know I probably sound like I have stock in Cisco but I can not tell you how impressed I am with the Cisco 4400 LWAPP controllers. In a nutshell the way it works is I have a bunch of APs out there setup and the controller is doing an LWAPP tunnel back to itself and controlling all aspects of the APs. The controllers uses APs to see other APs and compensates things like channel, signal strength, roaming etc. There is a software called WCS that you can use to control the controllers. You can also do a myriad of troubleshooting with WCS depending on the CCX level of your hardware. Use a predictor tool to setup your APs or better yet do a site survey with a variety of antennas. What is the objective public WiFI, IP telephony, LAN access? Are you planning on using b/g or A? Big antennas are great but they are only as good as the transmitter sending back to them (in most cases the wireless NIC in the workstation). When doing a site audit I determine what NICs are being used and base my audit points on whatever the lowest power/gain NIC is in the system. The controller will also tell you if you have coverage holes and loads of security things.

Here is a video and document for the controller.

https://www.cisco.com/en/US/products/ps6366/index.html

Here is a video and link for Cisco Wireless Control System (WCS)

https://www.cisco.com/en/US/products/ps7305/index.html