The benefit of organizational membership is typically proportional to the amount of activity you have in it. 1st year I joined APSA (ASHP,APha and stateSHP/PhA all with one coordinating board on the school level) as well as our AMCP and SIA (Industry) chapters. I was active in APSA on both APhA and ASHP side, went to both conferences, etc and learned quite a bit. SIA I didn't do a thing a basically just wasted my dues. The point is, if you're going to spend money on dues, you might as well spend time in the organzation and get something out of it.
Oh, and yes I went Greek. Happy with the decision. 1/2 our class joined 1 of 3 frats last year. 1/2 didn't. A few more joined this year, but not many. ~2/3 of the class of 2012 joined this year.