Lisa, you pretty much answered everything. I like to add that if you are looking for a free forum which is almost equivalent to vbulliten in features check out
http://www.phpbb.com. But vbulliten is the preferred choice for everyone since it offers support. I think you get a licensee for ~$85. check it out here
http://www.vbulletin.com/order/.
In order to set up phpbb.com, you need to download the lasted phpbb. 3.0 version, ftp it to directory where you want to install the forum (for example if you want the to forum to link to
www.yourdomain.com/forums., then make a directory called "forums" on your plublic_html folder and ftp the files there) and follow the install instruction on your hosting server.
http://www.phpbb.com/support/documen...stallation.php
I think most hosting companies have tools or guides which can auto install third party tools like forums on your website. You will have to search your control panel to dig out all those features.