Can I set the default simulator for new projects in Xcode 7.1 or latest?
You can select the desired simulator via the Hardware > Device > [OS] menu (Xcode 9):
While unchecking "Show as run destination" hides the simulator, this will also change the default value.
Updated image for Xcode 11.5
No need to delete simulators!
- Product → Destination → Add Additional Simulators...
- In the sidebar, select the simulator you want to hide
- Uncheck "Show as run destination"
Edit: Updated for Xcode 10