I love listening to all kinds of arrangements of classics - rock arrangements, jazz arrangements and folk arrangements. I have recordings of Trans-Siberian Orchestra playing rock and metal arrangements of many classical pieces, like Carol Of The Bells, Deck The Halls With Boughs Of Holy, Oh Holy Night, Nutcracker, Oh Silent Night; Alex Masi arrangements of beautiful Christmas Canons of Bach on a e-guitar; Jaque Loussier's Trio jazz versions of Vivaldi and Bach; Blackmore's Night, Loreena McKennitt's, V.Zinchuk's and Timo Tolkki's arrangements of traditional Greensleeves song etc. etc.
I play music myself alittle - I've mastered several unique Centralasian instruments, and my idea is arranging all these famous classical masterpieces in ethnic key, enhancing old Christmas hymns and carols with exotic oriental air
Overall, I think the main reason why classics is truly eternal is that it sounds great in any arrangements.