My PC is on whenever I am home... If its a workday, sometimes not at all, or occasionally in the evening.
As for my arcade, while its still not 100% complete, I expect a similar result. I would probably power it on in the morning, so that we could jump on it whenever we need, and power it down at the end of the day. It would not be on when we are away, or gone for the day working. I like the idea of it sitting in attract mode waiting for someone to come use it throughout the day though.