1TB seems a massive amount of space, have you looked at using
MDT? With this you can have a single image for each OS you require and make any changes using a task sequence.
What operating systems are you deploying?
How many different types of hardware?
Are you deploying software within the image?
If you want to deploy either Windows 7 or XP it is fairly easy to set up basic task sequences to perform the installation and then let group policy take over for the software deployment. If you are using the same software in most of your images you can import it into
MDT and set any silent install switches as required, these applications can then be installed during the installation of the OS. Similarly with hardware, if you have large amounts of the same model then you only need to import the drivers once and the installation will pick the correct ones and inject as build time.
If you want more information there are plenty of people on here who have got
MDT running nicely who will be more than happy to advise you. If you can give some more info on the background of what kind of setup you have then you could have a test system up and running in a short amount of time.
I know this doesn't answer your original question on hardware but in the schools we support we run
MDT on the server in school which has to do everything (DHCP,DNS,AD,File & Print server etc) and even when imaging up to 40 machines at a time there is no noticable effect on the servers.
Generally all servers we have put in in the last year will have been Dell T610's with between 8-12Gb ram and teamed Intel gig networking.