As a note on the unused music: sync the CD at 1:54 with the DVD at 3:04 (Region1, EE), it plays till Smeagol has gotten a deathgrip; it gives the scene quite a different feel. (obviously

) You can also see a short clip of the scene with the music still present on the sound documentary on disc four of the EE set.
The noise used over that scene was also used in TTT, and later in ROTK, usually when Frodo is being tempted by the Ring. (e.g. right before he claims it at Mount Doom)
As for the track as a whole, Shore obviously uses a similar musical feel for the Stoors as he does for the Hobbits. And there's a very nice rendition of the Ring theme; the last minute however, is what I was humming for weeks after I first got the CD.
TTbk