Network audit and survey software

We are an IT support company. When we sign a new customer, an engineer will visit their site and gather network related information that allows us to efficiently support the infrastructure.

Whilst we use GFI and roll this out through group policy, we would also like to gather information during the initial site visit, which will then be used to document the customer and present on our intranet.

I am looking for a product/tools that will allow a laptop to scan the entire network and provide the following information:
1. Hub/switch - including serial number and IP address
2. Server - make, model, type, IP address, installed software, software product numbers/keys
3. Printers - make, model, type, IP address
4. Wireless access points - make, model, type, IP address
5. Firewall/router - make, model, type, IP address
6. Client computers - make, model, type, IP address, installed software, software product numbers/keys

This may be a tall order, but I would like to be able to gather as much information from a single laptop as efficiently as possible. The gathered data should be presented in a way that is simple to format and manipulate.

Thanks in advance.