>With the new version of Visual Studio 2013, when I click on an .aspx file from my project, it opens it in Design mode instead of Source mode. With the previous version, I had to change a setting for that so I wouldn't have to do this one click per each .aspx file of all projects I maintain. Anyone remember where is that switch?

I don't have VS2013, but in VS2012 it is under Tools>Options. Then HTML Designer>General. There it gives the option to start pages in source view, design view, or split view.