Question for those who have taken the LSAT

[StopTheMorans]

Background: I'm 25, and have been out of college for 3 1/2 years. I'm going to take the LSAT in february. I haven't done any preparation on my own; other than taking an old LSAT that was administered as a practice test at a college last year (they were trying to get people to pay to take a prep class). I did well enough on that test to get into most of the schools that I'd like to apply to, despite the fact that I completely bombed the "games" section b/c I didn't know how to go about diagramming the different parts of the question in order to more quickly obtain an answer. But I'd like to do well enough so that I can go to any school that I'd like. Here's my question: have those of you who have taken the LSAT taken any preparatory classes? If so, which class/classes were they, and did you find them helpful and worth your money? Any info is much appreciated; thanks in advance.