With the Top5 list, you may want to start from the end of the list and work your way to the front. I suggested that one the other link I posed, but it would work for any of those. The last threads int he Top5 are newest. Last post was 3/30/2011
Also it is subjective to what people want.
eBook apps. I love them. I’ve read more having them on my phone then when I had an older phone without this option.
Kindle. Yes this is the Amazon e-book reader on Andoid. It’s free. In the market. You can download free or even books that cost money. Some are reduced in price and some are occassionally free (maybe for a limited time, so check that). You can do this from your phone or the amazon site.
Aldiko. This ones’ not bad. You can even get the Project Gutenberg books which are old, out of copyright books, on there (info on how to do that on the Gutenberg site). They also have free and paid books.
FBReader. I hadn’t heard about this, but Gutenberg has how they can do this with Gutenberg and mentions it’s an Andoird e-book. So it’s something to look into on the market and check it out.
Kobo. Another e-book reader. I haven’t used this one that much, but Have it on my phone.
Nook. The Barnes and Noble e-book reader on your Android phone.
Laputa Book reader. this one aparently has some books that aren't suppose to be ebooks, such as the Harry Potter books, they've never been digitized. So use this at your own discretion and decision.
As you can see, the eBook list can even be longer then this, there's some for library books that may or may not work in your area or you may choose not to use them (I haven't because they're not in my area).
So if I only suggested MY personal favorite, it would be Kindle. You might miss out on some wonderful ebook readers. That's why taking time to read boards is so important.
The Droid Applications forum has some all the time that a website puts out. For example:
Top Weekly Android Apps (28/3 To 3/4)
Top Weekly Android Apps (4/4 To 9/4)
Plus these discussions
Top Apps for Rooted
Whats your all time favorite apps?! (last post 3/16/2011)
Best twitter app?
The Droid Games forum has
Android recommend games overview
Best free games?
Top 5 Android Games Of Year
the Droid General Discussions forum has
Top 5 Apps --Categories - Requires You To Think!!
best clock widget to use?
The Motorola Droid forum has
Best "Notes" app?
The d X General Discussions forum has
Hope this helps in your search for the apps.