Chattaway's distinctive Species 8472 motif from "Scorpion" was used in the later 8472 episodes as well.
There were a number of episodes where David Bell got to do something other than the repetitive stuff he was usually required to do, allowing us to hear what a good composer he really is. He did some good Goldsmith-influenced Borg music in "Dark Frontier Part 1" (Part 2 was more his conventional VGR action music), and some interesting source music in episodes like "The Thaw" and "Remember."
Whatever one may think of "Fair Haven" and "Spirit Folk," at least they have some good Celtic-influenced music. I particularly liked Jay Chattaway's score to the latter episode, which had some great, lively music.