That being said, there are some edge cases. If you make extreme use of additional feature of amazon ( SDB/EIP/etc.. ) then the Amazon "bundle" could make it a better situation for you.
Im only writing this because I see so many HN'ers talk about "Well, I can spin up a extra large instance at any moment to handle extra traffic!" - The fact is, most of you dont do that. And even if you do, you would likely save money just being on a dedicated anyways. Cloud hosting is really for "overflow" and nothing more.
Again, Hourly billing- Cloud hostings biggest advantage.