I love my K1 but I would not buy one today. The K3 WiFi is $139 which cannot be that much more then the K1. The screen on the K3 is far superior, the memory is far greater, the capabilities of the K3 are just superior to the K1. Heck, collections alone make the K3 a better choice.
I would strongly recommend using a regular MP3 player for your music. The MP3 player on the Kindle is bare bones.