You may want to go for the Kindle Touch instead, it has every advantage of the Paperwhite except the light. If you value the light, think about the Paperwhite, otherwise, the Touch is just as good (well, besides for Japanese language support and capacitive touch instead of infrared. I doubt that that is part of your calculations, though.
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I personally would hate to use a Kindle Keyboard, just because the touchscreen is SOOOOOOO much easier to use.
Plus, you can usually get a Kindle Touch on ebay for about $75 plus shipping. And you can easily find one with 3G for the same price if you check lots of listings, which is a nice, FREE bonus.
I know because my friend got his Kindle Touch recently from ebay, and I helped him find one that had 3G for the same price.
I was too lazy to sell my Kindle Touch wifi and buy a 3G one the same way, though. But if I had a Keyboard I would upgrade in a heartbeat to the Kindle Touch.
So I think there are two things to consider:
1) Do you want to upgrade to touchscreen, and
2) Do you want a built-in light.