Ok I'll bite. I've seen several of these threads about owning both and have started to reply in the past and gave up. But, here goes...
I've got an iPhone 4, iPad 3, and a 13 inch MBA. All personally-owned devices. At work I've got a Dell laptop running Win 7 hooked up to two monitors.
I do marketing for a software company which is pro-BYOD. I use my work laptop when I'm physically in my office, hooked up to the corporate network, for during office hours content creation, initial doc creation, etc. and then I move projects via the cloud to my personal gear for after hours/weekends, or when I'm traveling. This helps maintain the "separation between church and state" since I'm willing to use my own gear for work, but not work gear for personal. I carry the iPad 3 and the MBA with me to work everyday, the MBA stays in my backpack and the iPad is used during my day job, primarily in meetings to check marketing metrics, look at webpages being discussed, etc.
However, I still use a Moleskine notebook for taking notes and sketching mockups of webpages, etc. I've tried several note taking aps. and sketching aps. and just like the old-fashioned notebook for this purpose.
At home, I run an eBay business where I part out motorcycles and sell old part stock from dealerships. I use a combo of the iPhone and the iPad as my scouting tool, checking classifieds, constantly running Craigslist searches and doing very basic maint. of my eBay store, replying to messages, checking auction status, making deals outside of eBay, etc. I'm checking the two iOS devices throughout the day, making sure my side business stays on the rails.
In addition to after hours work use, my MBA is used for inventory, auction photo uploads, and creating eBay listings. The eBay app. on the iPad sucks for listings, especially if you're doing multiple listings. I'll go on a "cook" (Braking Bad joke between my wife and I) where I'll marathon list over 100 items on eBay in one setting. You just can't do that with an iPad.
My wife has the same set up, iPhone, iPad, and MBA. She's a PT and currently staying home with our kids and on the surface would look like her gear is overkill. However, she uses her MBA as our central photo and video (every parent who has switched to digital knows that managing and storing photos and videos of their kids is practically a part time job) management point, backing it up to a Time Capsule, ext. hard drive, and also to the cloud. iPad for content consumption.
We recently cut cable (and don't miss a thing except Fox news, the app. still sucks) and have an ATV3 so we are using our iOS devices a fair amount around the house. We consume media with the iPads, our three year old daughter watches shows, games with the iPads and we also launch videos, movies for her through the ATV3 with the devices.
My wife is doing around 75% of her reading on the iPad. She still reads paper books, and uses a library card. She is using it to also hit the usual chick sites like Pintrest and that cool site where the mom reverse engineers furniture from Restoration Hardware and posts the plans up (We've built almost all of the furniture in our house). Three-year-old daughter has her own paper book library that takes up an entire wall of her room. We plan to keep her reading on paper through grade school but the tablets are competing (we also have a first gen. Kindle Fire that is basically her's for videos and games but she doesn't have total access to it).
I'm doing all of my reading and video watching on the iPad now. Novels, a lot of work-related content like whitepapers, ppts/pdfs., news, feature news, interests (mountain bikes, motorcycles). Mainly use Twitter and follow people or brands based on their ability to share or point to good content.
Ironically, we spend the majority of our time together as a family not using all of this technology. We use it to save time and be more efficient.
(I know, sucks to be me right?). I've found that I use my iPad for general "goofing off" and my Air ends up being my work from home computer mostly.
