Wipeout Pure on the PSP! The DS was only several months old, and I thought the games looked fine. They looked like advanced versions of N64 games, which didn’t really blow my mind.
But when I saw Wipeout Pure as a launch title for the PSP, damn near looking like a PS2 game at, for the most part, 60fps, THAT blew my mind. I had no idea how graphics like that were even possible on a handheld.