Hey there Syphix... Welcome a'board the convert train.
I, about 2 weeks ago now, moved from the horrid E* to the lovely, the beautiful, the wonderful DirecTV.
I thought I might tell you how I handled my move, since I was in the same situation as you - dropping the 522.
I left my Dish service online till my DirecTV equip. was installed and working just the way I wanted.
My installers took down the E* dish, and installed their stuff using the same mast.
When I called Dish I told then why I was cancelling, and told them that I needed them to send me the materials to send the leased equipment back to them. They needed all the leased receivers and the LNB(s) from the E* dish.
I think you'll be pleased with your switch. The Tivo is hand-over-fist better then any Dish DVR I've seen and used. I have also noticed a marked improvement in the over all picture quality.