I am wary of Bookshelf. I am unconvinced it has features that would make it worth paying for in the face of so many free options.
For those interested, I have posted a very comprehensive review of Stanza and eReader over at Teleread. Apologies for the two typos---I don't have my own posting account there, and with David in the hospital, I had to send this via in-line text in an email to someone else, and editing was a pain for both of us

I had promised this to David before he got sick, so I really wanted it posted. I'll probably wait until he's back in business before submitting any other articles
Anyway...
http://www.teleread.org/blog/2008/10...he-ipod-touch/
As a personal update, I have found I am just reading a ton on it now. I am used to the small screen. And I love it. LOVE it! I have got a great system going where I'll spring for a pricey new release on Fictionwise if it has 100% Micropay rebate, and then spend the Micropay on other Fictionwise stuff

I am keeping stats on what I spend versus how many free and paid books I read, and it is much cheaper than buying paper books

I think because the ipod is so small and convenient, I am pulling it out more than I would have with my eBookwise. The eBookwise is more of an 'I am planning to sit down and read for an hour' kind of thing. This is better for when I happen to be on the subway, already have it in my hand because I was listening to music on my way there, why not read until I get where I am going. I just am so loving the ipod and Fictionwise and Manybooks and the whole set-up I have right now.
My one caveat would be that I have no idea how hard it is to set up the network so you can download content without using a PC, and that worries me a little because right now I have free wireless internet included in my apartment. I share with my landlady, and she already had it going. When I moved it, I literally plugged my macbook into the wall, and there I was, on-line. Same with the ipod. It just found the network, connected me, and everyone was happy, books for everyone etc. If I did not have this cushy little already-set-up network, I ave no idea how hard it would be to get internet working on the ipod, and it seems you pretty much need wi-fi or internet to get books because you can't drag and drop from your computer.
But assuming you have a network that works for you, it is fun and easy. I am thrilled. It is just what I wanted.