My use tends to vary by season though, depending on where the warmth is, or (cool in summer) I also use my mini for work, the iPod and iPad are strictly recreational use
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At one end of the desk my iPad 2 is standing open, with the course-smart app open to a page in my textbook. At the other end my iPhone 4 is playing some Daft Punk to keep me moving.
In the center is my dual screen PC, which has amongst other things this forum open.
The funny thing is that since i bought MBA I'm hardy ever using my iPad.. It's much more convenient for me to take MBA when i'm on the go and there is internet access so the only use from iPad is in car while in traffic etc.
At the moment about 45% iMac, 45% iPad, 10% iPhone. That will change when I get the 4S, as the new toy always gets played with the most at first. I suspect that it will get about 20% of my usage. If the iPad gets siri that will drop down to 10% again.
I'm surprised that for many people on here the computer wasn't the number one most used. I guess this survey might indicate to some that its time to sell a few things, lol.