The King of Fighters I've been waiting for!!!
King of Fighters XI (HUGE improvement over '03) was the next one in the series but due to some unfortunate circumstances it couldn't be brought over to America and was very hard to find; so I never got around to playing it much. It used the team-switch system from '03 but added dream cancels and really unique cast of characters that still to this day aggrivates me that such characters have never shown up again(Duck King, B. Janet, etc.)
KOF XII was the first HD KOF for the next-generation. The game was real bad but had some promising concepts. The new art direction reminded me of SNK's other fighting franchise: Art of Fighting. Major problem with this game was that it lacked any story, moves, and hell - a boss. It was basically a demo for KOF XIII, but that's kind of tarnishing the good name of KOF XIII because I'd rather just play the demo then look at KOF XII again.
King of Fighters XIII is a KOF fans dream and should already be apart of their collection. For those not into the series it's going to be hard to get into because the combo mechanics are very execution heavy.
Great cast of characters, vibrant backgrounds, online(haven't touched it - no GOLD), loads of missions and trials to grind out. The full package is here and this game is hands down my Game of the Year 2011 and favorite fighter of the past decade.