I cannot stand reading on a computer screen, so I do not hold out much hope for the upcoming iPad from Apple. I went with a Kindle DX (thanks Brian Dennis :-)) for my R&S studies and I 100% love the device. Incredible native PDF support makes for enjoyment of all the INE workbooks and Cisco DOC-CD segments.
The digital ink concept is truly what makes this device so perfect, and I cannot believe more people are not talking about it as they begin to predict the demise of the Kindle at the hands of the iPad - or the version with enhanced memory and disk space - the iMaxiPad.
If you are thinking about an e-reader for your studies and you have questions, let me know in the comments below....
The most important thing is to enjoy your studies folks, paper, or electronic ink-based!