My power profile is pretty much "always on", although I let the monitors turn off after an hour of inactivity. I only reboot once a week, preferring to put the computer to sleep instead. However, I make a point of never doing this with SONAR open. I've never wanted to test whether this is really necessary, but it just seems like a good idea.
The biggest problem is USB ports being shut down and not coming back to life on wake-up. Fortunately, you can exempt USB ports from ever being powered off. Prior to Windows 8, that was an obscure setting done via the device manager. Windows 8 conveniently includes it in the advanced power settings. Maybe that's in Win7, too, I don't know because I've never used Win7 for audio.