Every original is in this package, why miss it?
Half-Life, Counter-Strike, Opposing Force, and Blue Shift on the other hand are marvelous games, Half-Life and Opposing Force take you through the story line of the original story, from Gordons POV and a soliders POV, Half-Life is the better game, but both are quite challenging at times. Counter-Strike, now 1.6, is probably the best reason to get this package, believe it or not. The other multiplayer games included don't come to par with this game though, #1 multiplayer game of all time, what can come to par with that?
The other games that you'll get, Ricochet and Codename: Gordon (Half-Life inspired 2D adventure game) aren't really good at all, but you'll have fun with Codename: Gordon more than Ricochet, mostly because Ricochet is rather clumsy and confusing. While Codename: Gordon is like another 2D adventure game, not as great as Sonic or Mario were, but still fun if you enjoyed the 2D's on the Genesis NES and SNES.
If your computer can't handle Half-Life 2, get this package, since with Half-Life 2 you get pretty much everything here anyway, but since this is only $19.99-$29.99 it's not a bad deal for what you get: a revolutionary FPS thats arguably the best PC game ever made, and the #1 multiplayer online game (not MMO, which has just become a genre in itself.)