I played the gamecube version at a friends party when I was in middle school. Later I played a lot of psu on the ps2/pc server and after it shut down I downloaded the game and played shtacks then came to here.
Hated dreamcast. one of my characters got hacked first week in. As a result, I'd have to say gamecube. On Friday nights, I would grab my infamous bag of Doritos and tear that game apart. Sadly, the game was too easy compared to dreamcast and; eventually, my buddy playing the game thought he was god or something. (I think it became too boring for him. Highest Ending character levels 123, 117, 96, 34)
PSO was my favorite game on the Gamecube, and I kept going crazy with it long after all my friends moved on to other things. I think it was my second true video game addiction, and I guess it's just fate that I'm back in it now. I never played any other version of it, and I never even got to play Blue Burst until I played on the Schthack server for a few months maybe 4-5 years ago. Despite my lengthy hiatuses (hiati?) from this game, I never, ever stopped listening to the music. I just went nuts trying to hunt it down, and it's been in my library ever since I've had my own computer.