Might be a nice idea to keep the buddy list down the left when viewing your profile & PMs too. Especially for the PMs.
Also, once the UserCP is finished you could remove the profile link from the header menu and just have people go through the UserCP for it.
Also, in the subscribed forums & topics there should be the option to unsubscribe in the listing in the UserCP
Just as a note, the Subscribed topics didn't work for me in your demo. I went to a topic and clicked "Watch this topic" and it confirmed I was watching the topic, but when I checked in my userCP it didn't list it.
I also couldn't find the "Watch this Forum" link anywhere. Don't know if you've implemented either of these yet, so just letting you know.
Another thing I just thought of too... would this MOD be able to integrate with the SpellCheck MOD at http://www.phpbb.com/phpBB/viewtopic.php?t=27134
. I think it would be cool if it could read the cookies the spellcheck mod uses to store users "Learned Words" and allow the user to add/remove words from them. (Obviously not a good idea to put them in the database... terrible duplication of data)
And while I'm on about other mods, would this be able to link in with the attachment mod too. Allowing a user to view the stats for their attachments and edit/remove them too?
Sorry if this post seems to ramble a bit, I'm just typing as things pop into my head.
Hope some of this is useful.
I'll be watching this topic