I have a ton of libraries, various organic pieces, but for symphonic, I tend to use Albion I the most. It doesn't give all individual pieces, more broad strokes (strings hi, lo, brass hi, mid, low, and winds hi, lo), but it is a great library for cinematic bits. I tend to augment this with Session Strings Pro, or Action Strings. There are many other libraries which sound as good or give more control, but Albion works for me, and does a great job at a reasonable price. Whatever you use, you will need to learn the library. Even when they are all in Kontakt, they are all scripted differently and to get the most out of any given library you will have to learn its particular expressions and articulations.