Whaleeyeman, that's a good one but what if on move 9 black moves his dark squared bishop to a5? I just take the knight on c6?
giuoco piano

BornQueen, well...correct me if I'm wrong, but that sorta takes away the advantage white has after the pawn sacrifice.

Yea, because of that d4 move, the whole concept of Giuoco piano stays alive as white keeps on attacking and does everything in the name of innitiative.

Try this gambit (don't remember the name, but gives you an advantage in the center :D)
absolute center control :)

Funnymadman, yea, the legendary Evan's Gambit. I never tried it, will try to watch some videos of this one too, thanks.

Try 5.d3 instead of 5.d4... leads to a quieter life, more in keeping with this opening's nomenclature.

Yea, because of that d4 move, the whole concept of Giuoco piano stays alive as white keeps on attacking and does everything in the name of innitiative.
Your knowledge about the opening is some 120 years old, at least. The truth is that white is struggling after either 9.d5 Bf6 or 9.d5 Ne5 (choice for Black is pretty much a matter of taste).
5.d4 is no more than equal for white, and certainly not after 7.Nc3?! - if he wants to get something out of the opening he has to play 5.d3, or the Evans gambit at move 4 (4.b4).

This is the line advocated by Dzindzi, which (with correct play from both players) is flat equal. GM Gawain Jones has employed it a few times, with average results. Radjabov also used it against Karjakin at a rapid game a few months ago, and lost convincingly.
And of course there is also 7.Bd2 Nxe4 (not mentioned at all by Dzindzi) and 7.Bd2 Bxd2 8.Nbxd2 Nxe4. Both seem to offer Black equal chances without much trouble.

9.d5 is the Moller Attack, which has been refuted. There have been suggested improvements on this game but I've never seen one that looked very worthwhile for White. Still, it can be playable in blitz and live games - providing you know more about the opening than your opponent.

This whole discussion has been enlightening and sort of dissapointing as the d4 opening got a thumbs down by most, with convincing proof to back their claims.
The quest for a good pet opening continues.

Yeah, I do prefer Evan's Gambit of 4. b4 instead of 4. c3. The gambit gives away the pawn but wherever the bishop goes you can go ahead with 5. d4. I dislike c3 right away because while you try to set up d4 black gets to move Nf6. The gambit (accepted) allows you to push d4 with tempo, gaining complete center domination and/or material advantage, whatever they play. The thing is, you don't want them to play Nf6, as it creates an equal game, and we don't want an equal game. We want a winning one :)
I'm a big fan of the Giuoco piano and see it as an amazing opening option for white, but I have some problems understanding some of it's concepts. You can look at this move sequence I posted here