If you are up for an e-reader, the Kindle is superb (for me).
There are app's on the net for converting your pdf manuals to Kindle friendly sized pages etc. and plenty of raw text books (ie free) out there.
I got mine two weeks ago and I've hardly put the thing down, I've gone through 8 books so far.
It was cheap enough to take a chance on at £109, but there are some downsides. The text to voice interpreter is great, as long as you're reading Hawkins guide to the universe - anything other than that it just seems a little odd :)
The browser actually works (over wi-fi) for emergency purposes, but too clunky for any other use, having to zoom in and out to move about on the screen is slow, but it works.