F12 brings up CPU debugger window?
In Delphi, if you're debugging an app which has F12 as a shortcut key for some command, then you're most likely going to get very ticked off by having Delphi "break" when you hit F12. This is because F12 is the "UserDebuggerKey" on Windows 2000 and above, by default. What this means is that if a program is being debugged, hitting the UserDebuggerKey will break into the debugger - and Delphi shows you a nice little CPU window.
To get rid of this problem, you can reassign the UserDebuggerKey by changing the registry. There's a Microsoft support page that details the key (HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug) and what values you can use.
I would think "Pause" would be a better key to use - makes more sense to me, since the only time I've used it ever has been in the boot process and when getting to the System Properties screen (WinKey + Pause). Both of which I'm unlikely to be desperate for when debugging.