I just installed Apache last night, and I have spent hours trying to get the user_dir module working. I configured with the options
--enable-module=most
--enable-shared=max
then made and installed apache.

Now, I've tried changing httpd.conf about twenty times, restarting httpd and apachectl each time. And I still can't access my own machine with
localhost/~username
or
[ip]/~username

I have made sure that the statement
UserDir public_html
is in the configuration file, and I have checked the permissions at least twice on each directory.

Even worse, now I tried changing the DocumentRoot to be explicitly the directory that I want, and I still see that infernal Apache test page telling me that my server is working properly.

I'm at my wits' end. Can anyone help?

Did you make the proper calls to LoadModule and AddModule in your configuration file?

Yep. I did.

They were inserted into httpd.conf automatically as a result of the configuration options I used. And they are not commented out or anything.