Does anyone know of any font families that 6, 9, 8, 0 look exactly the same upside down as right side up? The 6 upside down would look like 9 and vice-verse. Thanks!
As DA01 mentions, a search for "geometric sans" will give you great results. These are some of the ones listed under this category in Font Shop, the 8s are more irregular, but you can probably find some that are completely symmetric.
ICT Serif Gothic
Futura is a popular one
But the 8 is slightly bigger on the bottom than on the top, now that I look at it in photoshop.