so far, d5 is most popular
The Chess Game Forum

I like d4 and play is always as white
hit the forward button. white already moved.

d5............ 4 vote(s)
d6............. 1 vote(s)
c5............. 2 vote(s)
Nf6.......... 2 vote(s)

d5............ 4 vote(s)
d6............. 1 vote(s)
c5............. 2 vote(s)
Nf6.......... 2 vote(s)
Yeah