This might be interesting, but I was never able to get Silverlight working on my PC in any other browser than IE. Not in Firefox or Opera, even though they tell you they support Firefox. As long as it doesn’t work in any other browser than IE, I won’t deem it worthy for my time. Why use Silverlight when you could use ActiveX? Bah! :P
By that reasoning it seems a bad idea to use the word “always”. I hear Microsoft is fairly decent at getting OEMs to bundle MS software.