Thank you, Malife for your reply. We too have had similar experiences.
It's true my wife's Sony Reader 1st gen. reads PDF better than my Kindle 1 particularly on landscape.
While I understand the formatting is due in large part from the publisher I still don't understand how Amazon can still sell these books that essentially have unreadable graphics (tables, charts, images).
Last year, I too had to render some PDFs for travel but instead of going the Kindle conversion route or converting the PDFs to jpegs, I ended up buying an iPod touch and saving myself a lot of headache. The nice thing is that Amazon has offered Kindle for the iPhone so I can read my text based kindle books on my iPod touch. Unfortunately despite the ubiquitous pinch and zoom UI, Kindle for iPhone doesn't support it and images can't be zoomed in for magnification.

Plus not being e-ink, it burns up battery life and is more eye straining.
Oh well, here's to competition in the future and hopes for an e-ink reader that supports journal reading and other image intensive work without costing a ton.