The Soundstorm library is the best bang for the buck for a one shot library. Sound ideas is recorded rather boringly and it's vaguely out of date. The HD general library is more of the same. The Hollywood Edge is decent.
All the independants are the best value. Frank Bry (the recordist), Tim Prebble (a hiss and a roar), Tonsturm, Rabbit Ears, Takoma, CASound, Chuck Russom are all great recordists and have great material for less than it would cost you to just master a similar amount of recordings. Boom library is good stuff but too expensive for me to justify. Always keep an eye on the designingsound blog.
A great library:
Soundstorm $6000
Various Independents $2000
A used 702 and a used 416 or pearl MS8 in a rycote $5000