Aperture, Diablo 3 every now and then, downloading, watching anime, encoding and decoding movies, blogging, word documents, excel spreadsheets, power point presentations, outlook (yes all of ms office), print server (when docked at home to the thunderbolt display), salesforce.com, managing a sales team through california, etc.
I actually interchange between my Air and my Mini at home. The Air is the more powerful machine so if I need to do some heavy duty stuff such as encoding or decoding, I use the Air. If I'm leavin the house and need a computer on for a large download and to have the print server running, I switch to the Air. Or if it's a week or two that I go on a long trip I also take the Air.
I sometimes interchange between an iPad LTE and the Air as well. Most of my day to day tasks when I'm on the go can be done with my iPad LTE with the logitech ultrathin keyboard since I mainly need access to SalesForce, reviewing documents and spreadsheets, and sending emails. I am actually considering selling the 2012 Air 11" i7 since I will be upgrading to an SSD drive and 16GB RAM on the Mini. And if I need to access my computer from home, Splashtop running on the Samsung Galaxy S3 or the iPad work great. It just sucks when you sometimes run into rare situations when you wish you had a laptop when you're out and about to do a complex task such as PhotoShop or putting together a large presentation from scratch!