The ssh man page describes the -X flag, but says nothing about
configuring the daemon on the remote system.  Even with -v, nothing is
printed to suggest a problem on the remote system.  I suggest that
something like this be added to the ssh man page:
--- ssh.1-orig	Fri Dec 20 20:53:12 2002
+++ ssh.1	Fri Dec 20 21:07:44 2002
@@ -563,6 +563,9 @@
 .It Fl X
 Enables X11 forwarding.
 This can also be specified on a per-host basis in a configuration file.
+X11 forwarding must also be enabled in the \fBsshd\fP server
+configuration file on the remote machine (e.g. "X11Forwarding yes" in
+\fI/etc/ssh/sshd_config\fP).
 .It Fl C
 Requests compression of all data (including stdin, stdout, stderr, and
 data for forwarded X11 and TCP/IP connections).

--- Begin /etc/ssh/ssh_config (modified conffile)
Host talon
	ForwardX11 yes

--- End /etc/ssh/ssh_config