First of all there's nothing wrong with Silverlight. Netflix must be using Silverlight 2.0 which is Intel only, that's no big deal, since Apple already implicitly gave the "Intel only" okay when they announced Snow Leopard was Intel only.
Back to Silverlight, Silverlight is fine. I've been watchin MLBtv from mlb.com all year hooked up to my 50" Samsung LED dlp tv and it's been awesome. You figured Netflix had to go with Flash 10/Adobe Media Player or Silverlight and they chose the one that has been "proven".
I don't know why people are dissing it so much it's a VERY small download, it installs easily, and "IT WORKS". Except when MLBtv servers collapsed under load on the last day of the regular season when the Mets, Brewers, White Sox, and Twins were all fighting to get into the playoffs, Silverlight performed just fine.
Now if Blockbuster/MovieLink would get on board with decent cross-platform solution, I could get rid of my windows partition. Blockbuster/MovieLink has way more movies rentals available for rent than iTunes, but their reliance on windows media player really sucks. Perhaps Silverlight will provide a transition strategy for them.