Someone I know is interested in getting an Amazon Kindle for their family member.  After doing some search, I found that some of the Kindle's competitors are Barnes & Noble's Nook and Sony's E-Readers. I find the following to be pretty helpful.

• Amazon's user reviews
• Kindle vs Nook vs e-Reader
• Kindle 2 v Kindle DX

If you're interested in a Kindle, don't forget the accessories: Leather Cover and Mighty Bright.