
Personally, I think they finally made a Pokemon game worth playing when Crystal was released in the US.
My first time ever playing a Pokemon game was when I got my used Crystal cart at a store for 10 bucks. A few years ago I was given Pokemon Yellow as a gift when I got my first Game Boy Color, but I never really played it seriously.
So, I saw this used Crystal and had some spare change on me so I bought it. I had the chance to buy both Gold and Silver in the original Japanese, but I passed them up. Then, since having finally played Crystal (in English) I was really mad at myself for not buying them!
The milestones the Crystal game made were the main reasons I fell in love with it. They added a girl character to the series! Along with the addition of the girl character the other cool features, like breeding pokemon and shiny (alternate color) pokemon also made it an alluring game. The other breakthrough features were the expanded pokegear, and the addition of the cellphone feature.
Crystal is basically the same as Gold and Silver, but it has a few more interesting features and events. Some of the areas even have better graphics in Crystal, and some of the pokemon as well.
The graphics are, of course, a lot better than they were in Red, Green, and Blue. Yellow was a bit better, but they really hit the jackpot when they made Crystal.