Which is my next

I'm looking for some help choosing my next ebook reader.

I've been reading close to exclusively on electronic devices since picking up the original Palm Pilot about 15 years ago. Right now, I have a Sony PRS-505 and a BlackBerry PlayBook but the battery on my Sony doesn't hold charge as long as it used to, reducing one of the advantages of e-ink. The PlayBook is a bit heavy for long reading use, and I find it's not brilliant in portrait mode.

Things I like about the Sony:

  • e-ink really is more comfortable to read
  • great battery life
  • reads epub and a variety of other formats (RTF, PDF, and Sony's proprietary format are the ones I've used)
  • lots of hacks available for the firmware
  • included/integrated book-like cover
  • lots of hardware page flip buttons
  • nice steel shell and awesome build quality in general

Things I like about the PlayBook:

  • wifi + Dropbox client so I can keep my reading list sync'ed with my PC no matter where I am
  • can read in the dark
  • way faster CPU so it bogs down less on images and other hard to render pages
  • colour screen for book covers
  • can listen to music/podcasts, videos or even Youtube and Flash videos in the background while I read
  • my ebook reading app overrides formatting of the book if desired

Things I don't care about that other people seem to find important:

  • e-book stores, because I get most of my content from out of copyright sources or from my local library
  • dictionaries
  • annotations and notes
  • non-book reading functions like audiobook support, web browsing etc.
  • support from library software like Calibre

My feeling right now is that I'm looking for something like the Sony except a bit lighter, and with a backlight. Nice extras would be ability to change margins, paragraph spacing and font face and size on the fly (as opposed to me manually hacking an epub file). Custom user fonts would be great too. Gravy would be wifi and Dropbox so I could grab books on the run when I can't hookup the reader to my PC.

I read in lots of places, including on the bus, so one handed use is important for reading while standing up.

I'm open to suggestions for what other features of their book readers are useful or enjoyable.

Thanks guys!