We've always been a Sony Reader family, all the way from my first PRS-500 way back when. I also read on my iPaq PDA back then, and still read on it at the gym - I keep waiting for it to die from sweat, but it hasn't yet!
I've branched out since then, and I have a Nook ST, a Kindle keyboard, and a Samsung Galaxy Tab 7 Plus, in addition to my PRS-T1, but the rest of the family is pretty much Sony, all (husband, son, father) on PRS-300's which I gave them (and maintain), except for my lone cousin who has one of those basic Kindles.
And, with all of those e-readers floating around, I still read mostly on my Galaxy S2...