There are two options when it comes to budgeting your Google AdWords campaigns - you can either choose "standard" or "accelerated". Standard will basically throttle your budget throughout the day so you hit your budget cap right at the end of the day. Accelerated, on the other hand, will spend your budget as quickly as possible. If you set a low budget, you could cap out in the morning.
Now, let's say you have a pay per click campaign that works really well. You have set a really high budget so you basically never hit the cap. Even so, I recommend choosing accelerated spend. Why? You're telling Google that way to spend as much money as they possibly can. By choosing accelerated, you are now ensuring you spend as much as possible (and make as much as possible with your lucrative AdWords campaign).
That said, if you have a new campaign (or are constrained by a budget), standard is often the better bet.
energetic