So for what its worth, FIOS came in today and gave me the 150dn/35up Megabits package. I actually started out with the 35dn then moved to the 75dn. But I was still having issues.
My router/modem is in my livingroom. We wanted to keep it on the middle floor for wireless purposes. My HT is in the basement. I bought the Netgear Powerline adapter XAVB 1004 for the basement and hooked up my XBOX and Receiver to it. While it worked, because it was not plugged directly into the router my speeds were 45/dn when I signed up for the 75/dn. This was understandable and not bad, but there were still several times when I watched Youtube videos from my XBOX360 that in the middle of a 10 minute video I experience several independent moments of buffering. While I knew that the XAVB was slower, I still thought 45/dn would be more than enough, but it wasn't. So if it was not the speed, what could have caused those vids to buffer in the middle of the stream?
Naivley, I complained to FIOS and they decided to up me to 150 at the same price, Haven't had the chance to fool around with the new speeds yet, but I did have them place the modem/router in the basement. When I complete my HTPC build it will be plugged in directly into that. With that speed, how long will it take to download a 2hour HD movie? What are some things that I should try with my HTPC to take advantage of that speed to get the most for my money.