When I first saw The Straight Story when it came out, I was blown away, in no small part because of the pairing of the beautiful rural visuals with the amazing music, which seemed like an amalgam of country/bluegrass sounds, Badalamenti-synth, and even Spanish-sounding guitar. I looked for a long time for a soundtrack, and could never find one, until recently I saw it was release on iTunes.
I think I was high on this music for about 3 days, having it on loop on my mp3 player. It holds up consistently as an album, lots of changes of paces, between really heartfelt music and lighter pieces. To me it kind of contains the story of the film within itself (as I find a lot of good soundtracks do.)
I think I can definitely hear traces of the Twin Peaks soundtrack in here as well. Part of that maybe a given considering that it is another collaboration between the same two people, but some of the references sound deliberate to me. This track, Nostalgia, has parts that seem really reminiscent of Laura's Theme from Twin Peaks (and maybe even the theme from Invitation to Love!):
http://www.youtube.com/watch?v=TfIabTphLYk
Only odd thing: Tracks 2 and 4, "Rose's Theme" and "Sprinkler" are the exact same piece of music, 2.56min long - but I don't mind so much, it is an amazing piece.