Universal Sports is number one on my wish list, though I would like to see AMC HD and Lifetime HD (for Project Runway, primarily) too.
I'm a big fan of gymnastics and figure skating (and hockey, my husband likes skiing and cycling) ... All things Universal Sports offers a LOT of coverage of, usually live and very comprehensively.
I would never argue that there as many fans of gymnastics, track & field, skiing, swimming, cycling, or figure skating as there are of, say, football and basketball, but DirecTV has many niche channels, and there is value in having them even if I (one customer) will never, ever watch a single horse race, car race, wrestling match, fishing program or hunting show.
So far, Olympic sports are a totally uncovered niche, which makes it seem, to me, like a no brainer to add to DirecTV, if for nothing else but to enhance their "sports leader" status. And, right now, with the Games coming, would be the perfect, high profile time to make this addition.
Oh and, Universal Sports has a DirecTV action page here, where they ask that you write to DirecTV:
http://www.universalsports.tv/I_want_Universal_Sports.html