My computer likes the cowardly Kd3 putting the king safe, which made me laugh. It's second favourite move was d6 which has more of a point - fight for the center and let the bishop see the f7 pawn directly. Also after d6 then Qd5 would threaten mate on f7.
To my carbon-based eye h6 looks attractive. The cunning point is that the white queen eyes the unprotected black rook on h8. Pawns on e5 and g7 are the only things blocking the queen's gaze. The idea of h6 is to tempt black into playing gxh6.
Here are some sample lines (but check with the computer as the position is very complicated and the silicon monster sees a lot further and a lot clearer than me).
[fen "rnbqkbnr/pppppppp/8/PPPPPPPP/RNBQKBNR/8/8/8 w - - 0 1"]
1. h6 g6 (1...gxh6 2. d6 {trying to set up the mating threat Nd5, NXc7#} e6 {stopping that plan} 3. Nd5! {anyway!} exd5+ 4. Qxd5 {threatening mate on f7. Stopping it will cost black the queen}) 2. fxg6 hxg6 (2...fxg6 3. e6 {and the rook is lost}) 3. d6 e6 {and white is close to threatening mate with Nf6. Maybe first shift the black knight on g8 with h7.}