Yes I have both
I bought the new MBA 13" version this summer and recently updated the iPad to the ipad2.
The MBA is for the day job, hooked up to a big screen. I do things on it that I can't do / can't do easily on the iPad. Like, graphics, coding, ssh, moving files, talking on Skype, spreadsheets, multitasking etc.
The iPad is picked up right after I close the MBA lid. For twitter, magazines, general web browsing, like right now, YouTube, vod, email and stuff like moog and GarageBand.
To me they are 2 different beasts, I wouldn't want to be without either. I wouldn't confuse the MBA small size with being too similar to the iPad. The MBA is still a powerful workhorse and I bought it over the MBP for its portability and ssd by default which makes it very quick for 95% of my daily tasks.
It sounds like your requirements are very close to falling into the iPad bubble. So it isn't as clear cut for you but for me I have a defined need for both. I could use the air for my general stuff too but I like the convenience and usbaility of the iPad.
Ps... The pro would be a waste of money for your needs.