I wish I had some Sennheisers... I have been a victim to so many broken earphones that I probably should get some decent headphones.
Sir Psycho Sexy is probably my fav switch... goes from funky dirty sex talk to absolutely bliss. There's another one playing in my head... I just can't put a name to it at the moment.
EDIT: Got it... it's Jakob - Malachite. I don't know if it's quite what you're talking about as it doesn't greatly change the feel of the song... but I love the bit at about 5:10 where an extra guitar track is added over the top. Really kickstarts it before it finishes. Ehhh, I wish youtube audio quality wasn't so crap... it takes a lot away from the song.