Rizla
As far as I follow the treads at the-ebook.org, I would say there are some very well made packages from amutin and rupor. (See links
here)
Both packages bring all you need to read - e.g. Amutin: CoolReader / ColorDict
The problems starts when people try to make tablets out of there T1/T2. Messing with partitions a.s.o.