I would buy a Kindle DX for work if they had good PDF support. Most of our TECH docs are 11x17 format and some over 100MB. Without links, zoom, directory support or indexes current support is very poor. Cheap Kindle DX: Amazon's 9.7" Wireless BestDeal!
Not certain about the discount in that link; it ultimatevely resolved back to Amazon at $489.
Also do not know how well the DX works with PDFs in terms of bookmarks or indexes. But I just did a search in a PDF on my K2 and it worked pretty well. I searched on a term I knew occured several times, and it brought up a page with 9 hits, showing the hit in the context of the sentence, and easy to move to. But remember the Kindle's keyboard is NOT its greatest strength.