I used to prefer straight OSTs, but in recent years there have been so many great arrangement albums that I'm loving them more and more.
And yes, everyone should check out Dust's OST. Remember, it is listenable in full on HyperDuck's Bandcamp page. The game is great, too. A little bit repetitive, but considering the length and quality of the adventure, its easily my favorite XBLA game this year. I hope it can get a Steam release.