The best value there is!
You get a classic GotY title and it's expansion, you also get it's newly released expansion which is amazing in and of it's own. You get a multiplayer gem of a shooter that has been expanded into, what is now, the premier online experience and is a welcome addition to this collection. Last but not least you get Portal, a game that by itself is worth paying a full retail price for, this game is amazingly innovative and fun and will entertain you immensely, the dialogue in it will have you rolling on the floor holding your sides, it is just expertly written and presented to the player as almost a commentary throughout the game, this is by and large the best title in this pack, and considering Half-Life 2 is included, that is not to be taken lightly.
This should cost well over 100$ and you are getting it for standard retail price. It is too good of a deal to pass up and includes some of the best games ever released. There is no reason you should not own this.
I gave it a 10 for it's completely unrealistic price for its unbelievable content. This is just amazing