If you weigh yourself on 10 sets of scales you'll likely get 10 different readings. Scales are all calibrated differently so just choose one set and use those for your weekly weigh in. That said i would probably go for your electronic scales rather than the wii as I've heard a lot of comments about how unreliable they are.
I've found the opposite with my Wii - they weigh me heavier than my regular scales (regular on tiled floor, Wii on solid wood floor). Tesco sell their own range electronic scales for £6.00 and they are spot on! Almost paid £40 for Salter, and so glad I didn't. Tx
I have the same problem with a 5lb difference between normal scales and Tanita ones. I only use the Tanita ones to calculate body fat but a 5lb difference is quite substantial.
I normally just go with whatever one is lightest =)
Just stick to the wii, right or wrong it will still tell you weight lost.
(Just browsing the posts for inspiration, just about to start the Lighterlife programme, end of month.)