Guessed by @Ultrashroomz
Probably the best Pokémon game all-around. "All-around" in this case meaning it has shit tons of content, most of which is fun, has a solid story that doesn't get in your way too much, a great soundtrack, lots of cool Pokémon to catch and things to do both before and after seeing the credits roll.
Honestly, just listening to a song or two and typing a couple lines of text about it already make me reminisce. Like, the moment you remember what it was like to be playing this back when it was new, it's so glaring and depressing how far this franchise has fallen (and also apparently it's been 10 years, what the hell). This was Pokémon at its very peak, and it still blows my mind to see just how quickly they went from their best ever form, to the shitshow it's been ever since. For the past few years or so, I often forget I ever even cared about these games, but whenever I go back to replay these, it's always a great time.