"And they're here to play...Hot......(ssssssss)(smoke rises).....Potato!" This blew my mind as a 6-year-old.
I like how the current Pyramid intro starts with a shot of the set, which is then enclosed in a flipping trilon, rotating to reveal the logo. I also love how the Winners Circle trilons rotate from top to bottom once the logo swoops away. Probably one of the slickest game show effects I've seen in quite some time!
TPiR's current animation, with the Big Wheel and/or familiar pricing game props flying towards center of the screen, creating the logo, is a pretty cool one. It's even cooler during milestone seasons, when "40/45 Years" spins into place a la the Wheel.
The 80s Scrabble intro, with the tiles scattering across the screen, seemed pretty snazzy for 1984.
The Wheel of Fortune intro from 1992-94, with the wedges marching down the staircase.
Finally, the Scanimate effects used on Play the Percentages and Bullseye.