I'm always hitting this problem in one way or another and I've never really come up with a good solution.
I have lots of personal information (not secret, just that it's mostly only useful to me) which I keep in a Wiki. To make my life easy I run apache2 as user 'chris' (me) on the servers where I have the wiki. This allows me to edit pages directly and do all the maintenance etc. without the rigmarole of becoming root and/or becoming www-data.
However this then causes problems with other stuff that runs under the web server as they assume that it's going to run (in Ubuntu anyway) as www-data. My current hassle is with Owncloud which installs with www-data owning the data directory and I have to manually change the ownership to allow it to write.
There are also other similar conflicts.
Isn't there a way to tell the installation system that I want my browser to run as a specified user rather than the default (and really annoying!) www-data?
I suppose I could bodge /etc/passwd so that chris and www-data are the same but it is rather a bodge, I'd like a better solution.