Track 1: Foundations of Stone (9 MB)
This opens quietly, then the Aduin/Argonath theme appears. A pounding battle theme is heard, featuring choir and a really cool cascading motif in the orchestra. This section reminds me of the Khazad-dum sequence in FotR in sheer musical power, but is even better.
Track 2: The Taming of Smeagol (6.6 MB)
Opens very quietly with the Hobbit theme. It goes into some quiet choral music, which subsides, and Gollum's music appears. This is very eerie, and features a quiet Dies Irae-like motif played on cimbalom (I think). It's kind of a plucked-string sounding instrument. There is some more violent music for the confrontation between Gollum and the hobbits.
Track 3: The Riders of Rohan (9.6 MB)
This opens rather turbulently, with some rather exciting action music. This subsides momentarily followed by another theme, which subsides as well. Then the noble Rohan theme starts to appear, boldly stated by the brass in a glorious fanfare, and the solo fiddle. Absolutely wonderful!!
Track 4: The Passage of the Marshes (6.5 MB)
This is some scary stuff here, and is some of the best horror-type music I have heard. Lots of screechy scratchy strings, and whispering voices (which just send the shivers up my spine - can't wait to see this on screen!). The track closes with more subdued music and a reappearance of the Gollum theme on cimbalom.
For those that are interested, here is a picture of a cimbalom. It is played by striking the strings with very light metal mallets. It is an eastern european instrument (Romania, etc. and is a close cousin to the dulcimer. (Good thing I paid all that money for a music education, eh?)
I wasn't a huge fan of tracks 3-8 on the FOTR soundtrack. The ring wraith theme works in the movie, but it isn't something to go to sleep to.