On my Mini, I have the Stylz cover. Not a case. And I just stuff it in one of the pockets on my laptop bag. Which also has my wallet, power supply, phone(s) and chargers in it
Personally, I would go for a cover, not a case (cover = like a book, case = a box in which you put your reader). That's because when I want to read, I don't want to have to carry two things (reader + cover).