For those who live in US there's even better offer now:
http://amzn.to/pBQF8x
Kindle 3G with SO price dropped from $164 to $139, so it's the same as K3 WIFI without SO.
According to the article:
http://techcrunch.com/2011/07/13/kin...priced-at-139/ it's because of AT&T sponsorship, so it's unclear whether this price is temporary or not.