How to force Startup Manager menu to appear at every boot? Is there any way to force the Startup Manager menu to appear on every boot? Rather than me having to remember to hold down Alt if I want a different OS.
I'm not sure this is possible by default without holding down the ⌥ key at startup. You can make the Boot Camp partition always boot by selecting it in System Preferences → Startup Disk, but it sounds like this isn't what you want.  

However, if you're not adverse to installing additional software, I think rEFIt may do what you need. The section on Getting into the rEFIt menu says:


  If you have installed rEFIt on your Mac OS X volume, it will be loaded
  automatically when the Mac starts up.


You should then be able to select whichever OS you want to boot from there.