I got my PSP Street new in 2012 and had great times with it - Chrono Trigger, Chrono Cross, Jeanne d'Arc, Persona 3, Splinter Cell, God of War, SSX, Archibald's Adventures, Shadow of Destiny and moar. Playing Full Throttle through SCUMM on PSP was an awesome experience. Using it as a media player was great too until I got a smartphone. Can't say anything about DS, Nintendo has too kiddy presentation for my taste.
Deus Ex (2000) - a game that pushes the boundaries of what the video game medium is capable of to a degree unmatched to this very day.