At one time the non sports answer was easy, DISH clearly had many more channels in HD. Direct TV was clearly the carrier for sports. It has become muddled now and you have to a little more research to decide which is best for you, because Imo they are the two best carriers. It isn't who has more HD, it's what you watch and then who has it, and in what package.
At this moment, and only at this moment, it would appear DISH actually may be better for a college sports fan. That said, we do not know for certain if all games will be in HD, or if Direct TV will pick up more conferences. And I am assuming you are not in a DMA for NYC sports if RSN's are important, and remember RSN's are not full time HD with DISH, though most pro games will be HD.
I'm going to leave money out of this, unless you know the exact packages you want, exact receivers, how many of them, etc... there is no one who could tell you if it would cost more or less with DISH than you pay now. That said, very generally Dish probably will not be more, could be less.