How can I stop Spaces from taking me to an app's Space when I open a new file?
Found an answer on Macworld.com


  You can achieve the same thing in QuickSilver with and some basic
  AppleScript:


tell application "Safari"   
   make new document    
   tell application
   "Safari" to activate 
end tell



  Simply save this AppleScript somewhere that QuickSilver will find it.
  
  The good thing about the above AppleScript is that it doesn't mess
  around with focus (which can inadvertently switch Spaces).
  Unfortunately not all applications have a similar AppleScript command
  for making a new window (for example, Terminal does not).
  
  I saved mine in my home directory, and called it "New Safari Window".
  I also changed it so that it had the Safari icon (by dragging the
  Safari icon from the "Get Info" window of Safari.app, to the icon in
  the "Get Info" window of the new script file).