There is a feature of the Delphi IDE that is really hidden, because it requires you to add a registry key and cannot be enabled in the configuration dialog.
If you add the following registry entry:
HKCU\Software\Borland\BDS\4.0\Code Insight Sync Edit Params = "1"
You will get extended code completion. What this means is that this ...
... will not only insert ...
... but also prefill the parameters like this ...
SendMessage(hWnd, Msg, wParam, lParam);
.. and like Life Templates you can then use Tab / Shift-Tab to navigate through all parameters and change them.
To see this and other cool stuff in action, see Steve's demo
Unfortunately this doesn't seem to work with Delphi 2007 any more.