Can't launch X apps after 10.5.3, X11 update

Question

After upgrading 10.5.2 to 10.5.3, I was advised that I should also update my version of X11 (Xquartz) to the latest version (2.2.1). I did so, using the tarball on the Xquartz site, and my X forwarded apps have not worked since, via SSH or even locally. I'm not sure what I did wrong, but now launching X11 seems to launch two instances of the application (at least, X11 shows up twice in my open window list), and I get the following errors:
Local:
$ echo $DISPLAY
localhost:0
$ xclock
+Error: Can't open display: localhost:0+
Remote:
echo $DISPLAY
localhost:11.0
$ xclock
+connect localhost port 6000: Connection refused+
Both of these worked fine before the upgrades.

Answer 1

Understood. But from time to time, I have been required to upgrade certain packages at work separately due to vulnerabilities and bugs (OpenSSH comes to mind), so doing an update that claimed to fix some bugs in the native X11 version seemed to make sense.
Upon further examination, an answer was near the bottom of the very same page I'd just quoted:
+In a few words, you no longer start /Applications/Utilities/X11.app at login or launch the X11.app. You make sure the DISPLAY environment variable is NOT set, and then you simply issue the command, or click on the icon, or whatever, and the rest happens automatically.+
This seems to work: I un-set DISPLAY on my system (and removed it from my profile files), logged out of my sessions, and X apps worked without my explicitly launching X11. It's kind of nice to have X working again without having to first launch X11 by hand (or with launchd, if you can figure that out). I have to say that I'm nervous about seeing DISPLAY paths like this again:
/tmp/launch-RUXNTu/:0
... since the last time I had trouble with SSH, it was because this value was being forwarded on to remote hosts, to which this string doesn't mean a thing. But that doesn't seem to be happening now, for whatever reason.