Gameplay wise NRS era.
When it comes to roster, stages, music, and lore I think arcade was the best. I know you guys probably think im crazy saying that era had the best lore but I thought it worked so well because all we really had were the game intros, character bios, and character endings, and we kind of got to fill everything else in with our imaginations until the next game came out and told us what actually transpired. Maybe it was because I was younger but I always thought that was kind of cool.
Deception Konquest was fire though!