Nice. It does the trick:
In[12]:= xx=Tuples[{0,1},3]
Select[xx,! #[[1]]==#[[2]]==#[[3]]&]
%==Select[xx, ! SameQ @@ # &]==Select[xx, ! Equal @@ # &]
Out[12]= {{0, 0, 0}, {0, 0, 1}, {0, 1, 0}, {0, 1, 1}, {1, 0, 0}, {1,
0, 1}, {1, 1, 0}, {1, 1, 1}}
Out[13]= {{0, 0, 1}, {0, 1, 0}, {0, 1, 1}, {1, 0, 0}, {1, 0, 1}, {1,
1, 0}}
Out[14]= True
P.S. It seems that in this case, both SameQ and Equal work.
