My top 3 (in my nine years of FIRST)
2004 - So much to do and so many creative designs, this game was always non-stop action and excitement. I still love watching that video of 190 climbing over another robot to hang on the bar (I don't remember what off-season competition this happened at off the top of my head).
2002 - A game of great strategy (unless you were 71 and all you had to do is to not have your arm break (nations) or not get entangled (IRI (Thanks Baker!
))). In qualifing rounds, the winning alliances score was actually 3 times the losing alliances score. So if you dominated 40 - 3, you actually only got 9 points.
2009 - The reason I liked this game was because it was easier for the public to understand than what many other years was. It was fast paced and involved a lot of scoring (especially during elims and the championship).
I also would like to give a consulation prize to 2005 and 2006. I loved how there was such a big emphasis on autonamous mode where you recieved additional points for scoring the vision tetras or the most amount of points (you can contest 2004 was big with the 10pt ball, however most robots were not able to do this).