Hmm, good question. I agree with you, I think it's a mood thing. Dancing or working out, or any other time I need to get pumped up, it's definitely the remix. Working out, particuarly if I'm going for a run or bike ride, I get all "YEAH! Steppin' out of the ordinary!" *Cue the techno, pick up the pace* And then the original version is when I'm in most any other mood. Tired, relaxed,, thoughtful, or just in need of a little pick-me-up. Like I said, definitely on my happy-songs playlist too :)
I think we had a discussion in this comm a few weeks ago (maybe longer), too, about those full-circle songs like Proud and Sleep and possibly a few others. I think they're neat because they remind us of how far the characters have come and the journey we've taken with them.