For a pop song, you typically don't need a full orchestra. Strings, flute, oboe, english horn, french horn - you're mostly looking to add color to a song, not write a extended flute and string trio. Large number of articulations are generally overkill.

Don't worry about uniqueness. These are orchestral instruments, and you're not writing for sample library connoisseurs, are you?

GPO 5 is rather dated, but it's fairly complete. I'm rather fond of the flute and double reeds.

Amadeus will also get you a full collection of instruments. I find the english horn a bit underwhelming, and in general it lacks detail, but it'll get the job done. The "Symphony" patches will give you that "full blown" orchestral sound without having to work

BBCSO isn't complete, but it's got some nice sounds, especially the strings. No solo instruments - they're all recorded in pairs. But the price (free) for the student edition is perfect.

The Miroslav CE edition is has some lovely sounds in it. The sound is more "detailed" than some of the other libraries.

Having the full version of Kontakt will get you access to non-Player versions of Kontakt libraries, which is a good deal in the long run. NI's got a Summer sale coming up.

The full version of Kontakt comes with the Kontakt Factory Library, which includes - among other things - a fairly complete collection of orchestral instruments. That might be sufficient for your needs.

There are a lot of things that these sample libraries can't do. The Golden Rule of writing with sample libraries: write to the library's strengths.

Once you've got a core library, you can then focus on getting single instruments to fill the gap of what's missing.

For example, Embertone has a lovely Chapman Trumpet, for $30. They also have the Popelka Bassoon, also $30. There are plenty of libraries out there to check out, so you can find exactly the sound you're missing.

If you focus on getting a smaller collection of sounds that you like, you'll be less likely to go trawling through your collection looking for something that fits.

-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?