The iPad has become my "around the house" computing device. Most everything I do except for heavy word processing and gaming I now do on the iPad.
I've got a Dell laptop from work (I use that at work, obviously, and rarely use it at home unless there's a file or application I desperately need), an iMac and a 1st gen iPad. I had a MacBook Pro for a long time as my primary computer around the house, which was great for when I wanted to look something up on the web/check e-mail/etc., regardless of what room I was in.
But once I got an iPad I found that a lot of the everyday tasks I did on my MBP I preferred doing on the iPad instead. It's lighter, easier to move around, and the battery lasts a heck of a lot longer (if I'm doing basic tasks like internet/e-mail). So I ditched the MBP and got an iMac instead. I could sacrifice the portability because of the iPad. I use the iMac to store all my files and use it for ocassional gaming or when I have to do some heavy word processing (the iPad's just not fun to type on for more than a few paragraphs at a time).
The iPad has also become my e-book reader (replacing my 2nd gen Kindle except when I'm traveling and know I'll want to read outside), newsreader, and for the ocassional game or two. Yeah, I mainly use it as a consumption device instead of creation, but for what I need to do when I'm out and about, the iPad works perfectly.