A direct ethernet connection will always be the best way to connect your 722 to a network.
HomePlug is the next best thing since it does not require you to run a Cat5 ethernet jack to the location of your 722. Its limited to 14Mbps, but that usually is much more than most people's Internet connection speed, and most certainly more than the rate that Dish's servers will stream the data to you even if you have connection speed greater than 14 Mbps.
Wireless works too, but I am skeptical of streaming Video over a 802.11x connection. Sure it may work, but your saturate the medium leaving less for your laptop, or any other WiFi users.