One problem with using notifications, such as the excellent push notifications on the official WMPoweruser app, is that they may very well end up waking you up at night, as Windows Phone 7 does not include any way to mute notifications during certain hours.
If you device is unlocked, JMD Software may have the answer. Their latest app, Snotify, is a Windows Phone 7.5 application that silences notification sounds based on a schedule. The application will let you set a schedule to turn off notification sounds once a day and keep you waking up at nights due to emails, text messages or toast notifications.
The app needs access to the registry, so needs a fully unlocked phone or an unlocked phone compatible with WP7 Root Tools.
Those lucky enough to qualify can get Snotify at JMD Software here.