Hi, i was planning on getting a Nano at the same time i get a Touch off eBay. I will be using this mainly for exercise and biking (dont want Touch to fall out of pocket). The prices for a 4G used is usually around $75, and the prices for a 3G is around $60. I was wondering what are the advantage of the 4G over the 3G, or vice versa. One of them i know is colors. The screen size is the same and the 3G has an hour more of battery for video.