I said I'd follow up when I got my 360 returned to me from support. I actually got it back before I left for vacation a couple weeks ago. They told me it would take 10 business days round trip and I think I got it back in around 4-5 business days. They opted to just replace my unit and, sure enough, the new one is very quite. This was a pretty impressive experience so I filled out a very positive comment card.
To celebrate I purchased Lumines last night. I own a PSP and this was one of my favorite games so I figured I'd enjoy the sequel in HD on my couch... and I do. Gretchen describes it as "tetris on crack"... I would tend to agree.