I've removed everyting from my computer containing Silverlight in it's name. I ran Microsoft Silverlight Tools Beta 2 for Visual Studio 2008 after that. Silverlight 2 content appeared in my browser, but Visual Studio 2008 keeped crashing. I reran Visual Studio 2008 SP1 setup. It didn't help.
Finally I tried Microsoft® Silverlight™ Tools for Visual Studio 2008 SP1. It works. XAML designer works, Visual Studio 2008 doesn't crash!!! It seems Silverlight chainer doesn't contain SP1 tools. So don't forget to install it manually if you have similar problems.