All five of them. Started with Gold, then played Red, Blue, and Yellow. Then I played Sapphire, followed by Ruby and eventually Emerald. Then I bought a DS and Diamond, bought Platinum at launch, and imported Soul Silver from Japan at launch and HG when it launched in english. Then I bought White at english launch, and bought Black earlier this year for a Nuzlocke challenge run.
Haven't bought Black 2 or White 3 just yet, I honestly don't have the money to spend on vide games right now as I've got other far more expensive hobbies that focus on rare things, so games have to wait a few months.
Showing flashes of bravado, in a torrent of destruction, keep your head above the mayhem; clarity will be your weapon as the blinded falter and die.