I have Drive Image 5.0. A CD re-image of my gaming rig takes 12 minutes from boot to full operability. I don't really have a crunch time requirement so if the bulk of the repetitive work is done, not a big deal manually installing remaining software. I might rethink that once I set out to install software on 20 PC's! A good Final image will be an essential tool.
I'm thinking that with all games installed and XP you're going to have a lot of CDs for reimaging. Network imaging would be much easier and with a good network, just as fast. Not to mention that installing games individually would take forever. Punching it out simultaneously over the network and in most cases not even requiring the PC to reboot you'd be looking at an install time of maybe 20mins (initial install on one PC and then network broadcasting) for all 20 pcs instead of 10 mins per PC. And I would think that time would be an issue, if a PC is not able to be used by a customer than less $$$ for you and if you're downtimes are too long then it's possible some customers will avoid the place so they don't have to wait to play.
I'd better stop now.