I’m wondering the same thing!
If you don’t need user blogs, then don’t use WPMU.
This question seems to have replaced our old most-often asked question which was, “where may I download the theme used on this site?” 
If you don’t understand why you would need WPMU then 95% of the time you don’t need it. The only difference is with WPMU you can allow users to create their own blog.
Chaps I think the OP does actually make reference to understanding the essential difference between WP & WPMU
The question asked is whether there is some OTHER reason one is better over another apart from multiple user blogs, and I believe the answer to this question is no! BP runs just as happily on standard WP as it does on WPMU with the only real difference being no user created blogs just Groups and group forums and the one master site blog?
Andy is best placed to answer this though.
There is no difference other than user blogs.
WP and WPMU is set to merge at the release of WP 3.0 so hopefully this question will no longer need to be asked.
@rickbradford
…I want all member blogs on a single site…
If you want to offer your members their own blog, then you will need to use WPMU. The fact that each of your members has their own blog does not mean they have their own site. All the blogs are located on and served from your site.
If you only want to have one blog but offer a social networking layer on top of that using BuddyPress, then single-version (solo-blog) WordPress is all that you need. But, with both WPMU and WP, BuddyPress will allow you to create a social network. As Andy says, the only difference is whether you want to offer your members the option to create their own blogs on your site.
Yes, Jeff explains things much clearly.
You can use single WP and assign users a WP role of contributor or editor if you want users to post on the same blog.
If you want what WordPress.com offers — single user blogs — then opt for WPMU.
Thanks a lot, folks, I appreciate the feedback. Just to clarify:
I do want users to be able to create blog posts that funnel into a master blog (community blog). Whether they have a place that is their own blogspace is irrelevant as long as they never leave the site. In other words, a social networking site where a community blog is one of the features.
I think what I want is probably Community Blogs for BuddyPress (https://wordpress.org/extend/plugins/bp-community-blogs). The difference, then, would be this plugin means all posts go to a single blog and WPMU means all posts each have their own blog which are all served from within my site?
I’ve looked at some BP sites that have a list of blogs such as this one: http://dangerous-minds.org/blogs/
That’s WPMU, right?
Also, glad to hear they’ll be rolled in together with 3.0!
Ack, I just reread the last two posts and that makes it pretty clear. What a relief too!
Thanks again!
What if:
I want to have separate but linked subjects? Do I really need multiple blogs or can subjects be separated efficiently using groups and maybe activity streams?
I want more than one blog but I don’t want users to create their own blogs? Then do I need WPMU?
When WP and WPMU merge, which will be the better platform to be on to adapt to the merge?
Thanks,
Ed
This thread is going around in circles; I’m closing it. In a nutshell:
If you want to offer your members their own blog, then you will need to use WPMU. The fact that each of your members has their own blog does not mean they have their own site. All the blogs are located on and served from your site.
If you only want to have one blog but offer a social networking layer on top of that using BuddyPress, then single-version (solo-blog) WordPress is all that you need.
You can use single WP and assign users a WP role of contributor or editor if you want users to post on the same blog.
