It's a bit off topic, but I thought I'd point out how useful a Kindle can be for consulting. You can carry at least 500 reference books on it (and who needs more than 490 anyhow?). It is also very light and easy to read.
I do have a couple of qualms. It is a page oriented display (no scrolling), no touchscreen and has no spatial indexing e.g., the top side of the right page half way in, but other than that it's a win.
An important note on utility: O'Reilly e books can be read on the Kindle. The truly great thing about O'Reilly's e-books is that you get both the Kindle compatible mobiPocket files and the more aesthetically pleasing PDF files (for me, aesthetics matter--even in a SQL guide).
You can mix and match reading and reference between the formats depending upon your preference. Thankfully the files aren't copy protected. Thanks, O'Reilly, this is a very nice touch.