Curiously, the Sharepoint 2007 State Machine and Sequential Workflow Templates are missing in Visual Studio 2008 Standard Edition. I'm going to install the Enterprise Edition of Visual Studio because I know that they are present in them.

 It took a while to figure out they were missing, but finally when I checked "%ProgramFiles%\Microsoft Visual Studio 9.0\Common7\IDE\ProjectTemplates\CSharp\Workflow\1033" folder, the 'VSTOSharePoint2007WFSequential.zip' and 'VSTOSharePoint2007WFStateMachine.zip' files were missing

I guess they were excluded because they were part of the Office Development tools thats missing from the Standard Edition. Standard Edition users could try obtaining the above mentioned zip files, deploy them in the 1033 folder and see if the templates work. (Caution: It may be illegal to do so! So, do it at your own risk!)