NCIX is local for me, they are the very definition of reputable. Check the site, they really encourage user participation with the incentive program.. leave enough useful feedback, and you get huge discounts
For way cheaper drives, check eGlobalonline.com
They don't have DW1640 yet, but it will be cheaper when they do. I've never paid shipping for these guys, but I do business with NCIX and eGlobal all the time. Expect awesome customer service, esp. if you speak some form of Chinese.