Wow, I haven't heard the term "iBook" in a long while. Today, most cell phones pack more power than those models. Unfortunetly, Apple isn't in the market of supplying the masses with functional, cheap, and effective computing anymore ( RIP iPod ).
If you want a portable computer for reading and researching, light word processing, emails, etc. and you'll always be around a Wi-Fi spot then I'd go with a chrome book (running Google's Chrome OS). It's basically the same thing that the old iBook's did.
I wouldn't say the iBook is good for anything now-a-days-- since you'd have to be running really old versions of OS X... which means you would be more liable to security compromises. Chromebooks are super secure (mainly because the user can't mess anything up).