Gen 4 definitely. I spent so many hours (300+) playing Diamond when my mom would take me to work with her over the summer. I think I got to like 412/493 caught for the Pokedex with very minimal GTS trading. The music is so nostalgic and everything was so fun, it was just the best.
If we're talking style-wise, Gen 5 was the best. The sprites were perfect (really wish we would've kept them instead of going to 3D), the changes were nice (Poke Center + Poke Mart = GOD BLESS), and the story was so deep and interesting. Truth vs ideals... is it really okay to capture and "own" Pokemon...? I just recently replayed White and it was beautiful.
If we're talking style-wise, Gen 5 was the best. The sprites were perfect (really wish we would've kept them instead of going to 3D), the changes were nice (Poke Center + Poke Mart = GOD BLESS), and the story was so deep and interesting. Truth vs ideals... is it really okay to capture and "own" Pokemon...? I just recently replayed White and it was beautiful.