>>40220862Pokemon Black and White. Great graphics (if you can set up the emulator), amazing music, interesting locations, and fun gameplay. It's pretty much a definitive Pokemon game to me personally. And it's not even nostalgia, I played it only a few years ago. Loved it.
https://www.youtube.com/watch?v=B6yXDacQq38Another option is Heart Gold and Soul Silver, many people consider it to be the best Pokemon game overall.
Although I still haven't played it.If you want a pure Pokemon experience without fancy graphics, fancy gameplay features, or fancy anything (but also not a completely antiquated Game Boy title) then you can play FireRed/LeafGreen, a remake of Gen 1. It's a remake of the original game and little else, for better or worse.
And then there are last two gens, XY and Sun and Moon. I would personally recommend Sun and Moon because it felt a lot more refined to me, but it also has a bit too much dialogue for some people (or at least the original version does, USUM was better in that regard). They have much better graphics, the gameplay loop is a bit more refined, but everything else is kinda meh, really. They are a bit too easy for an average player. Besides, I don't think it's a good idea to start with them and miss the classics.
Also, here's a list of opinions Japanese fans generally had. I think it's a pretty good list.