The Scotch is a solid line, but it defuses the central tension immediately, which allows Black to equalize too early. For white's third move, It is a close 3rd behind the Italian game in popularity on ChessTempo, while the Ruy Lopez is the overwhelming favorite. The Danish gambit (4 c3), if accepted, can give white a strong edge in development, making it the one I like to go to. Scotch gambit (4 Bc4) can be countered fairly easily with 4...Nf6 or 4...Bc5.
The Scotch Game

Still, most people expect the others to play the Guicco Piano or Ruy Lopez; not something that breaks open the center.

Why can't we play 5.Nxc6 instead of Be3
Either Be3, Nxc6 or Nb3 are played most frequently. After Nxc6 though Qf6 threatens mate, which will be stopped by blocking with the Queen (Qd2 most usually) and shutting in the bishop. Then Black can recoup the Knight.

i had rely bad xp wit dis when da guy basicly trded off everythin nd got to an endgame were i got k'pooooned
The Scotch game is an uncommon opening getting ready to get popular. I, for one, play it, and think it is a very aggresive opening with many variations.
For the scotch game, there are not many book about it. One GM on Chess.com made a chess video lesson about it, so you should check it out.
The scotch game is very aggresive. The main line is on the board here:
For white, many people will not even hear about the Scotch. As black, many people have studied the main lines of the Ruy Lopez or Guicco Piano, so they won't be expecting such an aggresive move of 3. d4.
Thanks for reading my post on the Scotch Game!