I used wine 1.4-rc4 from the wine PPA on the winehq.org website.
First, create a new wineprefix.
Next, I installed .NET 2,3,4 using winetricks (winetricks dotnet20 dotnet30 dotnet40). For .NET 4, you'll have to get the latest winetricks. (See the Wine Appdb page for .NET 4).
I also installed vcrun2005 since Firefox crashed many times complaining about msvcp80.dll
Then I installed silverlight 5 (developer version - I think I used the 32 bit version, not sure).
Tried a few silverlight apps from the Silverlight showcase site. Only one of them actually showed anything, it started loading and even got to 100% once but then got stuck there and wine did show some errors but I couldn't make out what the problem was.
As for netflix, logged in, site loaded tried to resume a movie that I had been watching before. The page loads, I get the spinning blue thing but it gets stuck after a few seconds (just like the other silverlight apps). Not yet there, but Wine is moving closer.
Oh and I forgot. The plugin keeps getting stuck, CPU usage shoots up to 100%. After logging in, I had to kill plugin-container so that the main page would respond. When trying to play something, the same problem occurs.