Is there a VNC Client for OS X that can send Ctrl+Alt+ Delete? I've googled, searched have not found. I frequently VNC into Windows machines and need to send this key combo in order to log in.
iTeleport is my VNC client of choice, and does precisely this.
Apple Remote Desktop can send Control Alt Delete:
If you use Remote Desktop to administer a PC that's running VNC, you may be wondering how to send the Ctrl-Alt-Del command (Control-Alternate-Delete) from a Mac to the PC. Though Mac and PC key mapping differs, you can use an alternate key combination in Remote Desktop 2.0 and later to send the command.
For full-size (desktop) keyboards, use Control-Option-Forward Delete.