WF 3.5 is dead. WF 4 is a from-scratch developed workflow engine. WPF and Silverlight has many incompatibilities that lead to some work-arounds for developing an application runs or both and Silverlight has much better control set than WPF (In WPF you can not give the Media element a byte stream as source!). J# is dead. IronRuby and IronPython have not a decided fate. F# is in an ambiguous situation. And Microsoft's claims for supporting HTML5 just remembers me of IE6! If you had a ruined code-set (Like our team (Some in J# and some WF 3.5) you would react differently (IMHO).