Welcome. Here's my two cents worth;
Kindle - if you want to download (direct from Amazon) to the reader without needing a computer (almost had one but backed out)
Sony PRS-505 - if a brand name is important (got the PRS-500)
Bookeen Cybook Gen3 - if you want to have access to dictionary lookups and good access to plenty of books from various sources. (got one - this is what I use)
The above represents the most popular E-ink readers in the US. However you might look for references to the
Astak Mentor on this forum. It will be out soon & looks very attractive.