I am the same way, when I need to record a video and encode them I use my iMac, but my main machine around the house has definitely shifted over to the iPad.
I have to agree with some of the others. There is no way I could replace my Mac Pro with an iPad. Unless I stopped doing anything but browsing the web on my desktop.
My Air on the other hand, I have only used it for testing. I am hesitant to get rid of it, but I think I will and get an old Macbook for testing.