I used to run my arcade PC 24/7 as it was a server and a multimedia portal. Guess it depends what you use it for, and what kind of electricity bills you can afford.
Before you guys jump me on the pennies vs PC usage issue, I'll say its a cheaper way to warm a room.
Wear and tear is a factor, but I'm from the old school of computing where the PC SHOULD be on 24/7 365 days a year, as the turning on and off actually wears the computer down.
If your arcade cab is powered by a Via C3, then I would run that 24/7 definately, but if it is a heat generating AMD monster then I would leave it up to you. Properly ventillated should pose no problems.
So there you have the Should and Is it OK? answer.
Just ask the elecky bill payer first....
