Mike, there’s a Vol.2 of Zimmer coming out very soon as a follow-up to our (2007!?) 2CD set.
What I did with "The Best Of" was to get out some of the newer tracks we recorded and combined it with some of the better bits of our Zimmer back catalogue.
But if you have Vol.1 and get Vol.2 you'll have them all. I believe the 2nd Volume will available both digitally and on CD in the US and Europe.
"it’s surprisingly difficult to get hold of quality recordings of a lot of Horner’s music. Compared to the major releases of other film composers, the CDs of Horner’s music are often short and poorly mastered – as if the directors didn’t believe in the music as a central part of the films. So I’ve found myself waiting for remastered re-issues that never came. Fortunately, in 2011, The City of Prague Orchestra released The Music of James Horner,"