You can use Ghost Solutions Suite, Acronis SnapDeploy, or Microsoft Windows Deployment Services to image the machines.
What you want to do is install a Volume License copy of Windows and Office on 1 machine, then customize it how you'd like with other software and preferences. You can customize the user profile as well by making changes to a profile and copying it over the Default User profile.
The Volume License makes the key part much easier. You can use the same VL key for all of your computers. All of the computers do not need to have volume licenses. Microsoft gives you reimaging rights with Professional operating systems. This means that you are allowed to use your volume license media and key to image any computer running the same version of the operating system regardless of whether it has an OEM, FPP, VL, or any other license. Details are here.
After you're done customizing it, create a sysprep answer file. For XP, the answer file is created with a tool distributed with the Windows XP Deployment Tools. In order to have it prompt for a computer name at startup, leave the COMPUTERNAME option blank.
For Vista and 7, the answer file is created with the Windows Automated Installation Kit. If you are not joining the computer to the domain, you can simply leave out the computer name option in the answer file in order to have it prompt for a computer name. If you are joining it to a domain, it becomes a little trickier. There are some workarounds for getting this working available here. You may have to trial a few answer files to make sure it's as touchfree as possible. Some things I remember off the top of my head that you'll want to specify are localization, local administrator username and password, timezone, and network location. I recommend grabbing an un-sysprepped image before you start trialing out your answer files. If it doesn't work, reimage, alter your answer file, and try again.
After you have your answer file, run sysprep, shutdown the machine, and gather the image. Setup a multicast session to send this image to the rest of the computers. Multicast kills network performance for anybody else on the network. If you can, stop multicast traffic at the switch. If the switch does not support that, consider unplugging it from the network while you send the image.
The multicast session shouldn't take long. Maybe up to 30 minutes depending on the size of the image and speed of your network. When it's done, all the machines should reboot and prompt for a computer name. Enter the computer name, sit back, and reward yourself with a nice cold beverage :-)