Still Losing Subscribers, Dish Network has lost AT&T as a marketing partner, as the telecom giant has switched to Dish rival DirecTV.  Although Dish still maintains a healthy subscriber base, DirecTV is surging.  It performs well against the cable competitors.  It boasts partnerships with the three largest U.S. phone companies, appeals to the higher end of the pay-TV market and its stock is trading at 18 times current year earnings estimates (compared to 8.7 for Dish).  Observers think Dish must improve customer service and, perhaps, enter into partnerships with retailers that combine consumer electronics sales with first-year service contracts at the point of sale.  Dow Jones Newswires Sept. 29, 2008