Hmmmm.... buy a 500$ bike, ride it for a year, then spend 300$ upgrading one aspect of it? I dont think so! Buy the disk model, enjoy the disks their still going to be better than most (if not all) rim eaters, and then when you choose spend 150$ for better disks such as avid bb7's knowing that you already have a disk ready wheelset. Then if you wish you can spend that other 150$ on whatever, maybe a better rear derailleur, maybe a professional rebuild on the bike, maybe several parts at once 150$ buys a lot of parts especially if you haunt ebay ( dont include second hand shorts on this list).