On Sony platform definately Wipeout on both PSP and PS3, amazing games, AAA titles, best arcade racers... yet poor sales. And GT PSP deserves a lot more love, that game is mindblowing for handheld, heck it can be directly compared to console titles like Forza and full GT.
MY HYPE LIST: 1) Gran Turismo 5; 2) Civilization V; 3) Starcraft II; 4) The Last Guardian; 5) Metal Gear Solid: Rising