Not even close for us. Three iPhones and two iPads, only one iPad backs up to the cloud.
We have purchased the 25gb plan but I'm running out fast, my phone is 12.7gb back up size, while my wife's is 9.2 gb, and daughters being a short 2 gb. we are almost out with the iPad bringing up the rear, I'm highly considering purchasing the 50gb plan, i can't afford to lose data and the cloud is just way easier and better than the computer.
Well Yeah, the free space available at so many of the free storage sites make it more than enough for me, and I never felt need for more ID! as someone mentioned above, its enough for me and my wife :P