Next month I'm hoping to be able to afford one of the rpg sourcebooks.  I know, there is the option of saving up to get both, but let me assure you that my ability to save hasn't improved since I was six years old and spent my allowance the same day.   So it is only an option for people with better impulse control. 

That being said, which book should I get first?  I don't have a tabletop group at all, and haven't for years      I still keep buying gaming books, and dice, just in case.  I have all my really old D&D books, the 3rd ed books, some WW stuff, old Gurps, and the sourcebook for Firefly/Serenity.    I'm not a gaming newbie by any stretch, but I am new at this game.  So I want opinions on which book is best to get right now, and why, please. 

Also, if you're in Central Illinois and need a player...