Tried out my Roku XD last night and it seems to work quite well. Video quality from Amazon Prime actually seemed a bit better than what I have been getting from Netflix, though I haven't compared the same movie on both yet. My receiver doesn't have HDMI, so only stereo sound for the moment until I upgrade. I was pretty impressed with the video quality using the Roku though. I don't know if it makes a difference, but I also added a 2GB SD card to the Roku even before I fired it up the first time. I had a spare laying around from an old phone.
No more cable bill. There seems to be more than enough content for me to watch. I will just be missing a few things, but I may just sign up for Hulu+ also and that should keep me relatively current on the few shows I do watch.