Some have asked for my over all rankings:
I didn't want to change the original post, so I'll give my brief update here.
Again, just 1 sentence per unit:
Personal Ranking: (September 18th 2009):
#1:
iRex iLiad, Sony 505 and Amazon Kindle 2
I love iLiad's OS (free zoom for PDFs, renaming eBooks or authors on the fly, ...), Sony 505's design, touch & feel and compactness. I love the Kindle app for iPhone/iPod touch and Amazon's bookstore (usually cheapest and biggest selection).
#4:
Sony 300, Sony 600 and Cybook Opus
I'd rank Sony 600 even higher, but I don't have too much use for its touchscreen. I slightly prefer Cybook Opus over Sony 300, mainly because of the autorotation of the screen. Sony 300 more or less is even to Sony 505, but I find myself preferring 6" over 5". 6" for me is mobile enough and 5" sometimes just doesn't have enough information per page.
#7:
iRex 1000S, Cybook Gen 3 (Mobipocket version), Sony 700, Amazon Kindle DX
For iRex 1000S and Kindle DX, same applies as for the 5" units: I slightly prefer 6" over 8+". 6" does offer enough information per page and feels in my hand like a "real" book. 8+" is a bit bulky, hard to find the perfect holding position. Sony 700 is a nice unit, but I prefer Sony 600's screen quality. Cybook Gen 3 is a great unit, but I prefer Sony 505's design for example.
#11:
BeBook
Still the same: Don't like the design. I don't "enjoy", holding it in my hand.