EXCEPTION: There are two types of cloudbursting that are in wide use and capitalize on the benefits public cloud has to offer: horizontal burst and vertical burst. Vertical cloudbursting refers to intracloud application burst when your application lives in a cloud with enough room and resources to burst up to a certain percentage. This is intracloud burst because it's bursting into the same cloud in which it's living. [Also see: "Gartner: Cloud computing's most over-hyped terms"]
Horizontal burst, or intercloud burst, is how bursting between clouds is working most commonly right now, but it isn't following the "burst-into" philosophy commonly thought of. Rather, it refers to moving other smaller applications off to the public cloud purely so you have the room and resources to allow your private cloud applications to burst within their private cloud without reaching capacity. There may be no more benefits from moving those smaller, stable workloads off to public cloud other than allowing room for your private cloud applications to be able to burst.
Based on the characteristics and life cycle of enterprise applications running in the cloud, you should start to have a good idea what will and won't work. You shouldn't try to shoehorn cloud into your strategy by dumping every app you have into public cloud immediately; it might not get you the most efficient, economic results possible.
Don't just rush to pick the applications that are consuming the most pain, or consuming the most resources, or the most data. Chances are those are your mission-critical apps which could be highly integrated to other apps that would also need to move to the cloud. Cloud is not a cure-all prescription for your IT pain points; rather it works harder for you when you're strategic about which applications are placed in which environments. Success is about executing a total cloud strategy for each application.