Adagio is one of the ones I'd mentioned; I've seen it titled on Youtube as "Further Exploring the Temple Of Baa," which is where I got that title from. It starts quite similar to Bach's Toccata. That bell tolling in that and the cello really made that song. I dare say that one is my favorite.
I'd neglected to mention the one from Frozen Highlands and Kreigspire, but that is another track that I loved hearing.
I've found that in New Sorpigal, it seems to have three different tracks, and that it picks one randomly when you arrive there. The one I like is on Youtube, titled as "New Sorpigal Theme."
It's obvious that the people from NWC took great pride in their work. That MM6 and MM7 are still quite fun now, twenty-plus years after their releases, speaks volumes.