Of course, I play it vanilla first so I can appreciate how the sprinkles I put on the second time around interact with the flavor.
I like to replace the OST's in my games with foreign .ogg files. Sometimes, I find that I even improve the experience quite well. For example: Risk of Rain's Hive Cluster recycles the level theme from Sky Meadow which does not fit the level very well. Serendipitously, however, those levels have .ogg files that are seperate from each other so I was able to replace Hive Cluster's level theme with Agoraphobia by Earth/The Bug.
I've found gameplay of that level with no commentary and no in-game music playing so you can watch the audio tracks for both of these videos in this youdubber link:
http://www.youdubber.com/index.php?video=LO1lLx0Ag5Y&video_start=5&audio=mZ_22R7ZGMw&audio_start=0