The packaging says that you're getting Metal Gear Solid 3: Snake Eater in the Metal Gear Solid HD Collection, but that's not quite true. The reality is a little sweeter, as Hideo Kojima has confirmed that you're actually getting Metal Gear Solid: Subsistence.
For those who don't know, Subsistence is an enhanced version of Snake Eater. As well as the regular game, it also contains the MSX versions of the original Metal Gear and Metal Gear 2. That's like, two extra games, man.
The Japanese version of the game is going to be different. It won't, for example, include Peace Walker, but instead has a product voucher for the PSOne Classic Metal Gear Solid. Weird!