I'm trying to get them in order and not overlook any. I've included those I bought for my Mum as well as I'm the eReader buying addict here. By the way ... is there a therapy yet for this?
I still own, or rather we still own, all these devices and all bar a couple work perfectly fine still. Touch wood!!
eReaders:
Sony 505 (mine/ours)
Elonex EB600 (Mum) bought so I could get my Sony back.
Kindle Keyboard (3rd Gen) both wifi and wifi/3G (3G mine)
Kobo Touch (Mum) - starting not to recognize micro sd cards.
Kindle Touch (Mum
borrowed)
Kobo Glo (Mine - now Mums)
Kindle Paperwhite
Nook ST w/glowlight
Kobo Aura (mine)
Elonex 621EB (Mum - replacement for original)
Ectaco JetBook Lite (mine)
Sony T2 (mine)
Tablets/Others:
Palm IIIc (first 'eReader' device) - still own and works when I can find the right cables for newer PCs.
Imagine (5" tablet/reader - Mum) battery beg. to die.
Kobo Vox (still own but don't use - newer apps not working b/c of age of android installed)
iPad (3rd Gen Retina) - use this for more mags than books.
Google Nexus 7 (2012 - mine)
Nook HD - this is my default tablet type reader.
I can - at a pinch - read on a backlit screen but it tires my eyes and I prefer the eInk displays for reading text. Also less disturbances/interruptions. I'm easily distracted so cant seem to dive right *into* a book on a multi device like a tablet ... and also the eyes problem backlit screens give me.
I think that's them all now.

For now at least.