I suspect part of the equation is whether one buys used or new.  The difference in cost between the base and the S for a new car is pretty significant - but I think it diminishes over time.
I bought my 2000 S a month or so ago after having driven a friend's 2000 base model, and it feels significantly sportier to me than his did.  Of course, I drove his like it was his, and I drive mine like it's, well, mine.   
 
 
That said, I have no regrets over shelling out what looked to me to be the extra couple thou it took to get the S model of that age over the base model.