SoundCenter: The Complexity of Strings

I've been an amateur MIDI musician since '96, and I've only been using Sonar for two years now. (There was a 10-year gap in which I wasn't composing.) Despite my effort to learn the software -- and music theory in general -- one element is perplexing me: how do I choose a stringed instrument with my very basic knowledge of them?
 
In particular, I'm referring to String Ensembles. Back in '96 (during my first MIDI project), my "go-to" option would be String Ensemble #49 or #50 (choice of a fast or slow attack). Now, with my Cakewalk SoundCenter Modern Strings and Orchestral Strings instrument packs, the selection is much bigger, and more complicated.
 
I can't begin to wrap my brain around the 130+ instruments in these two packages, as many of them sound identical. There's no longer one "go-to" String Ensemble like back in the General MIDI days. I know there's no straight answer to this question -- but out of all these instruments, how does one choose the right stringed backing track to fill the mood accordingly?
 
Any suggestions for this troubled (still) amateur would be appreciated. Thanks!