On the topic of Shatner vs Takei here is a good (long) interview from the Howard Stern Show in late 1994. It sheds light on their different sides of the story. Convo about Takei starts around 8:10. Bonus: you'll hear plenty of George's "oh my" sound drops throughout.
Takei said it first; during the release of Generations it was already a common phrase on Howard Stern as per the story in mediame's video. I remember watching Generations in theatres and -- being a Stern listener at the time -- finding the line to be an odd choice, but I'm sure it was...