Can I change the behavior of the Home and End keys on an Apple Keyboard with Numeric Keypad?
One option is to create ~/Library/KeyBindings/ and save a property list like this as ~/Library/KeyBindings/DefaultKeyBinding.dict:

{
  "\UF729"  = moveToBeginningOfLine:;
  "\UF72B"  = moveToEndOfLine:;
  "$\UF729" = moveToBeginningOfLineAndModifySelection:;
  "$\UF72B" = moveToEndOfLineAndModifySelection:;
}


Quit and reopen applications to apply the changes. Note that DefaultKeyBinding.dict is not supported by some applications like Xcode or Firefox.

In Terminal you can assign home (↖) to control-a and end (↘) to control-e from Preferences > Settings > Keyboard. That will leave you with no key combinations to scroll to the top or bottom of a window though.

It might be easier to just use the default keybindings. In most native text views:


control-A or option-up goes to the beginning of a paragraph
control-E or option-up goes to the end of a paragraph
command-left goes to the beginning of a line
command-right goes to the end of a line