after suffering and using many e-book reader i was able to but my hand on an
e-book reader which together and calibre are consider my Reading heaven.
its simply eReader ,
why its the best for my point of view :
first i have nokia 5530 which is very similar to 5800, but what we consider here is that it doesnt have Keyboard which means that any nonsupport touch screen reader is pain in the ass .
there is ofc Virtualkeyboard app but doesnt give the comfort look when u read while the keyboard is visible .
another good reader as Mobi reader V5.3 (not official released),
it support touch screen in fact and u can switch pages using volume keys
but u stuck at full screen mode so u have to close the app .
there is also other apps see
https://www.mobileread.com/forums/showthread.php?t=99631
but i found that ereader is the absolute top reader ,
first of all its free reader and u can download it from its official website
sec there is huge libirary in the site to buy ready to download E-books
but for free world users -like me

- u can simply download the E-book u
want and convert it to PDB .
eReader can display Palm "doc" files, which have a Creator ID of REAd and a Type of TEXt, and files in PML format, which have a Creator ID of PPrs. eReader won't see other PDB files, in RAM or on a card.
(Quoted from DMcCunney)
so i for the last two days r converting PDF,TXT and other formats to PDB
to use it an eReader whcih i can spend too many words describing its advantages
but i hope u try it for ur self