How to bring my application to the front?

Here's something simple that seems to work, tested with multiple boxes consisting of XP, Server2003, Vista, Server2008, W7. Test application ran with a standard (or admin) account, stole the input focus from notepad while writing in the foreground.

var
  Input: TInput;
begin
  ZeroMemory(@Input, SizeOf(Input));
  SendInput(1, Input, SizeOf(Input)); // don't send anyting actually to another app..
  SetForegroundWindow(Handle);

You can tweak it further f.i. for a minimized app or such if required.

I am doing something similar in one of my applications and this function works for me in xp/vista/w7:

function ForceForegroundWindow(hwnd: THandle): Boolean;
const
  SPI_GETFOREGROUNDLOCKTIMEOUT = $2000;
  SPI_SETFOREGROUNDLOCKTIMEOUT = $2001;
var
  ForegroundThreadID: DWORD;
  ThisThreadID: DWORD;
  timeout: DWORD;
begin
  if IsIconic(hwnd) then ShowWindow(hwnd, SW_RESTORE);

  if GetForegroundWindow = hwnd then Result := True
  else
  begin
    // Windows 98/2000 doesn't want to foreground a window when some other
    // window has keyboard focus

    if ((Win32Platform = VER_PLATFORM_WIN32_NT) and (Win32MajorVersion > 4)) or
      ((Win32Platform = VER_PLATFORM_WIN32_WINDOWS) and
      ((Win32MajorVersion > 4) or ((Win32MajorVersion = 4) and
      (Win32MinorVersion > 0)))) then
    begin
      Result := False;
      ForegroundThreadID := GetWindowThreadProcessID(GetForegroundWindow, nil);
      ThisThreadID := GetWindowThreadPRocessId(hwnd, nil);
      if AttachThreadInput(ThisThreadID, ForegroundThreadID, True) then
      begin
        BringWindowToTop(hwnd); // IE 5.5 related hack
        SetForegroundWindow(hwnd);
        AttachThreadInput(ThisThreadID, ForegroundThreadID, False);
        Result := (GetForegroundWindow = hwnd);
      end;
      if not Result then
      begin
        // Code by Daniel P. Stasinski
        SystemParametersInfo(SPI_GETFOREGROUNDLOCKTIMEOUT, 0, @timeout, 0);
        SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0, TObject(0),
          SPIF_SENDCHANGE);
        BringWindowToTop(hwnd); // IE 5.5 related hack
        SetForegroundWindow(hWnd);
        SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0, TObject(timeout), SPIF_SENDCHANGE);
      end;
    end
    else
    begin
      BringWindowToTop(hwnd); // IE 5.5 related hack
      SetForegroundWindow(hwnd);
    end;

    Result := (GetForegroundWindow = hwnd);
  end;
end;

Another solution is not to steal focus and just put the window TOPMOST in the z buffer:

procedure ForceForegroundNoActivate(hWnd : THandle);

begin
 if IsIconic(Application.Handle) then
  ShowWindow(Application.Handle, SW_SHOWNOACTIVATE);
 SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOACTIVATE or SWP_NOMOVE);
 SetWindowPos(hWnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOACTIVATE or SWP_NOMOVE);
end;

You can't do this reliably. Windows XP had a workaround that would allow it, but versions since then prohibit it for the most part (see note below). This is expressly stated in the remarks section of the MSDN documentation on SetForegroundWindow:

The system restricts which processes can set the foreground window. A process can set the foreground window only if one of the following conditions is true:

• The process is the foreground process.
• The process was started by the foreground process.
• The process received the last input event.
• There is no foreground process.
• The foreground process is being debugged.
• The foreground is not locked (see LockSetForegroundWindow).
• The foreground lock time-out has expired (see SPI_GETFOREGROUNDLOCKTIMEOUT in SystemParametersInfo).
• No menus are active.

An application cannot force a window to the foreground while the user is working with another window. Instead, Windows flashes the taskbar button of the window to notify the user.

Note the final paragraph of the quoted documentation, especially the first sentence.

The problem with

this is for purely personal use and I want it to happen; it will not disturb anything.

is that any application could try to do the same thing. How does "purely personal use" tell it's you personally and not just any application? :-)

Note: I've tried everything I can think of to get the IDE's documentation to show in the foreground when I click the help toolbutton, but all I can get is the flashing taskbar button (and I as the user want it to do so).