The best opening piece sacrifice

I like the muzio gambit

Of true sacrifices (not ones that just win on the spot), my personal favorite piece sac in the opening is the reverse Halloween after white plays g3 in the four knights.  It's close to sound, it's playable, it's fun, and it's a lot better than the version with white:

EDIT: the most important difference is that when white plays this, the kingside has not been weakened with g6, so there are better resources for black than there are for white - paradoxically, white's extra tempo has given him a harder defense against this gambit.  

Surprised no one mentioned this:

Question how many muzio gambit are there?

I thought the Muzio Gambit was in the Kings Gambit were they sack a knight on f3?

The "Ring of Fire" in the Smith Morra is a good example, which begins with a Nd5 sacrifice.

Kutford Gambit (just made the name up) - queen sac in Pirc defence as white. Unfortunazely I'm on mobile phone so cannot post it. Anyone kind enough to search through my forum topics to find it? :-)

Here it is: www.chess.com/forum/view/game-analysis/queen-sacrifice-in-pirc-defence

How about the Fried Liver? Not effective on the highest level, but playable on amateur level.

@ Mandy : Shabalov doesnt give bishop for free, since taking it will lead to troubles on h file.

This is a common pattern!

About the sicilian, i am always impressed by the Perenyi attack :

Created almost 40 years ago, and i don't think a clear statement was found, even with computers!

I believe there was a King's Indian in which Uhlmann sacrificed his queen in the opening and drew Karpov.

That's a known queen sac line in the Samisch, IIRC.  I'll try and find it.  

EDIT:

Neither of these is a piece sacrifice. In the first case Black gets a rook and a pawn for two pieces; in the second Black immediately regains the piece if White takes the knight.

I think this should also be mentioned:

Black gets a nasty initiative.

I tried it and I lost.

Wow

Tal's 11 Nxe6 in the World Championship Match
https://www.chessgames.com/perl/chessgame?gid=1032520

Or this one