Antivirus for a enterprise network NOD32 or Avast?

I have gone through the features and prices of the above two and both of them seems to be fine and have good reputation in the forum though I found NOD32 is slightly high in price for the initial purchase.

I need your suggestion which one to go.

My setup is having about 70 ~ 80 Windows PC's connected to Windows 2000/2003 Servers and Exchange Mail Server.

My main expectations are:

- To Install and work with a good less resource hungry AV software
- Centralized virus definition updates (to save bandwidth)
- Enforce all the network connected devices are installed and having updated AV software
- Reduce the IT Administrators work

 

I don't think it is necessary to explain why . It is well know that NOD32 is faster , lighter and better in detection than Avast . Moreoever NOD32 detects all kind of threats including viruses , trojans , worms + spyware stuff + even rootkits . Avast detects only viruses/trojans/worms + chosen other things. NOD32 is very easy to manage through Remote Administrator Server/Console and it is automatic so it doesn't need to have Admin sitting there all the time ... So I can only say :
Use the best , leave the rest ! NOD32