I've got reader apps on both of my iPod touch units, but I never use 'em. I infrequently use them on my iPad mini, generally when that's all I have on hand. Ditto for my Asus Transformer tablet. I also have desktop apps on two computers, which I don't read with often at all, but I have to have a PC in the loop to buy Adobe-protected books. I suppose you could count my twin Palm T2s as being capable of being used to read, and once upon a time I did use one for that, but these days I only use them for their database app. Basically, I don't like using those things as readers.
I bought a Kobo Wifi unit when Borders was closing, then passed it to my mother when I upgraded to a Kobo Touch. The same thing will happen pretty soon, when my Kobo Glo comes in - so count me as having one Kobo unit. I also own a Kindle Touch that I'm in no rush to upgrade, because I only bought it for access to Amazon-exclusive content and sales.
So, all told...two readers, two sometimes readers, and half a dozen if-I-must readers. And that doesn't include the two computers I could dig out of mothballs if I really had to.