Lu Tang Chen (gold-suited guy with the sunglasses who chills outside Nagai Industries)
As cool as he was, I kinda felt sorry for the guy. It's like Ryo's the only one he ever interacts with, and he just spends all day smoking cigs, waiting in the freezing cold. He genuinely seems to like Ryo sometimes n'all. Not in a "let's be friends" way, but in a "yeah, that kid's alright". He also had the most interesting story of all the NPCs, imo. While most peeps look forward to a "Ryo returns to Yokosuka" epilogue so they can watch a nice, happy-clappy ending with Nozomi, Gui-Zhang, Ine-san, and Fuku-san, I'd wanna see it just to know where the guy ends up.
Other than that, I always liked Yamagishi-san, Mayumi (Megumi's hat-wearing sister), Shinkichi-san (seafood guy with the plaster across his nose), Nomura-san (cab driver), and Saijo-san (of Bar Yokoska). Also, Yada-san (Alpha Trading Office guy) always struck me as the kinda guy with the weight of the world on his shoulders. I was always pleased to see him. Even when he sacked me. The cunt...