Silverlight 2 may not have the control set that Flex developers are used to seeing out of the box but there are a significant number of control vendors who are stepping up to the plate to fill the void. It seems as though Microsoft's strategy has been to get the Silverlight 2 runtime out as quickly as possible (and as lean as possible) always knowing that this type of extension to the framework would exist.
I do still hope to see Microsoft push a little further in controls that are downloaded once and only once with the framework itself thereby making our applications leaner - but it's a pretty serious tradeoff until the runtime has the kind of penetration that Flash enjoys.
Anyway, here's a nice post from Tim Heuer that does a good round up of where to find those missing controls.
http://timheuer.com/blog/archive/2009/01/28/comprehensive-list-of-silverlight-controls.aspx
