[murraypaul]

I thought I'd post a summary of what I've found out so far, in case others are interested in the same query. Please correct me if any of this information is wrong or out of date.

Bookeen Cybook Gen3 - Single book list order by title or folder location. No means of filtering or searching for books. => Unsuited to large libraries
Allows loading of custom fonts. Reported to be faster in operation than Sony. GPL violator?

Hamlin V3 - Allows browsing by folder structure. => Ideal for large libraries.
Harder to get hold of than Sony, less 'comfort factor' of buying from a well-known company. SDK recently available, development may open up.

Sony Reader 505 - Allows browsing by title or author, including jumping to points in the list based on first letter. Books can be tagged as belong to a collection, and can browse a list of all collections, then all books in a collection. => Workable for large libraries, not ideal.
Large amount of ancialliary applications for preparing and formatting books to Sony format, but development on the device itself is not open. Most easily available and mainstream of the ones I am considering.

iRex Iliad - Allows browsing by folder structure. => Ideal for large libraries.
Development is open, reasonable sized development community. 8" screen compared to 6" for all the others. Touchscreen is unique selling point. Poor battery life compared to other readers. Is it a tablet PC or an ebook reader, or both? Wifi on more expensive version. Costs considerably more than other readers.

Kindle - I have no interest in the Kindle, being outside the US, but what what I can tell from the manual it allows browsing by title or author, including jumping to the first letter, but does not have anything equivalent to the Sony Collection tag. => Unsuitable for large libraries.