Thanks to everyone! Yep, packages that should have been present were missing. In particular, xbase-clients (which contains startx, which was indeed missing) and xfonts-base as folks suggested. Are these kinds of problems common in upgrading to Woody? Donald mentioned that he'd seen xfonts-base missing on a few upgrades. I have no idea why xbase-clients was missing ...
I installed the missing packages and now X works fine! And now I know a lot more about selecting X servers and troubleshooting by reading the logs (for some reason, it didn't occur to me that X would have logged stuff; I'm still learning). Thanks again! Jen
