Well....
If you don't want to spring for an iPad, you could go with one of these.
The spec. say that you can store .pdf file, that would be a requirement for me. On my iPad I store all the .pdf version of the avionics manuals. ".txt, .rtf, and .doc files are not currently supported."
I also store my charts, but that is another app.
The 1Gb of storage should be enough as all my manuals only amount to 100MB.
Kent