just in case everyone didn't see my description, the Withings Smart Body Analyzer is easily the best. It doesn't just do weight, but also:
- BMI
- indoor air quality
- fat composition
- heart rate
Also syncs very well with mobile apps and other services, in addition to of course wifi and bluetooth uploading of data.
It doesn't come out till April 18th, so it's the newest one and top of the line.