Let the hive mind of Engadget get that for you.
"I've found myself using my PC for a lot of conversations lately, and I'm also considering recording a podcast to share with anyone who will listen. There are tons of USB headset / microphones out there, and I'm hoping someone has some solid recommendations based on experience. I'll consider both headsets and standalone mics, by the way, but I'd like to keep the bill under $100 if possible. Help!"
I am assuming that you are refering to 1080p rather then 1080i. And trust me, I wish I could see it but there is nothing out there right now that has that type of content. There are some Windows Media HD clips but I had no way of getting them on the screen with my test equipment.
Even if you are refering to 1080i there is not much difference between 720p and 1080i due to frame rates. 720p is 60 frames a second and can make a smoother image while 1080i is 30 frames but has a higher resolution; on a 50-inch size there is not much of a difference. Plus, when you add in MPEG 2 compression thanks to DirecTV, there is NO difference. That is why they are upgrading to MPEG 4