If you could move any piece to any open square on the board for your first move, where would you go?

pawn @ d2 to h7

As white?  Pawn from e2 to e4!!  :-)

a2 to e5.  it activates the rook and puts another pawn in the center.

Ooh, here's another idea -- how about Bcb3?  Putting both bishops on the same color!

Bfb3 ... Developing a kingside piece to prepare early castling while aiming at my opponent's kingside.

I wouldn't want both my bishops on the same colour at all.  To clarify, my choice was for Bfc3.

Has to be an empty square according to the OP, rich.

Really interesting exercise. After a bit of thought I will go with pawn on a2 to e5. Someone already said it but anyway it makes the most sense to me. You turn an outside pawn into a primary central pawn and inhibit blacks development quite unpleasantly while gaining a half open file for the rook. I guess the only detriment would be the slight weakening of the b3 square.

Another couple of possibilities (that might turn out to be not so great with proper investigation) are putting the c1 B on g3 or the f1 B on b3.  [edit: this was said already too]  I can't imagine too many moves putting a piece out into the game on a different square than they could have gone to on move 1 anyway being any good. In the majority of situations I think black could just gain tempo driving it back.

If you could launch a mini-nuclear attack as a first move and anihilate all enemy pieces in a 3x3 square radius, what square would you hit?

just jokin.. this "off the rulez" questions are kind of crazy but still fun. btw I like the bfb3 idea.

I would take the king side rook with my queen

Great question! I like the idea of putting a bishop on the 3rd rank.

Maybe the pawn on b2 going to e5 or d5 might also be good? Allowing the dark squared B to fianchetto early without having to play b2. Of course this would weaken your pawn structure (creating an isolated a pawn) and some squares, so may or may not be better than a2e5. Wow, this problem is going to get stuck in my head now.

Ke3

Qh8 rook odds of course

It must be an empty square.

wouldnt it be? black can give rook odds cant they?

I like rust blade's strategy

e6 then f7. Ha ha ha.