There are so many really great libraries, and developers, it's hard to figure where to start!
For general symphonic stuff, and especially cinematic orchestral stuff, I think Cinesamples is the best. Not yet perfect, but really great sounding, and very playable brass, winds, and percussion. (caveat - I'm not a fan of EastWest's Play engine, so I don't use their Hollywood Strings, Brass, or Winds, but they are great sounding!)
Strings are tough - my favorite is LA Scoring Strings, but Cinematic Strings is a different approach and also sounds lovely.
Concert Strings 2 and Concert Brass 2 from Kirk Hunter are worth a listen - I still turn to them often.
For a wide array of everything from conventional to bizarre check out SoundIron and 8Dio - they used to be Tonehammer. Unbelievable value, and they both run the gamut! I especially love their percussion libraries, and their more experimental stuff.
OrangeTree is, for me, the best guitars and basses. I am a guitarist, and I still use them a little!
Indiginus Torch s another amazing guitar library, and you might want to check out Impact Soundworks as well.
For more sound design type stuff check out Heavyosity Evolve, or the newcomer Project Alpha from Hybrid Two.
There are a lot of choir libraries, if you need that sort of thing check out Cinesamples, 8Dio, SoundIron, and another newcomer, Stresov Sampling.
Wavelore is likely the company that sold you a pedal steel library. I'm kinda bummed, but their steel sounds better than my real steel. They also have a couple of resophonic libraries that are cool, but be forewarned, they'be been difficult to reach lately.
Bolder Sounds has some great stuff, including a really useful banjo.
HollowSun has amazing synths, and synth-like stuff.
SampleTekk is still my favorite for pianos - acoustic and electric - and they have the original 10CC choir from I'm Not In Love, which is a lot of fun to play with, even it if does suggest a particular song<G>!
I probably have, or lust after, some other stuff, but that's what comes to mind!