Difference Zen And X Fi Which Should I Buy: Creative Zen, Creative Zen X-Fi Or Microsoft Zune?!?!?

Which should I buy: Creative Zen, Creative Zen X-Fi or Microsoft Zune?!?!? - difference zen and x fi

With a view to buying an MP3 player 8GB new ... My main problem do send playlists on the fly, because my current MP3 player (Samsung YP-K3, which I published 2 years do not you let me and it excites me!) Sustainability is an issue is strong and the battery life. Please tell me your opinion! also built large differences between normal and Zen X-Fi speakers .. other than the X-FI?