The way I typically do this in my server setups is to create a group for the website, then use a combination of setgid and umask to make sure that files remain writable by the applications I want. Step by step guide below:
1/ Create a new group for your website:
$ sudo groupadd web-grp
2/ Add the user the webserver runs as to the group:
$ sudo gpasswd -a www-data web-grp
3/ chown the diretories and files that you want the server to have access to:
$ sudo chown -R :web-grp /path/to/website
4/ Set the gid bit and other permissions on those directories:
$ sudo chmod -R ug+rw /path/to/website
$ find /path/to/website -type d -exec chmod g+xs {} \;
5/ Set your ftp program's umask to 002. This will depend on your ftp client and server, search around to figure out how to do this for your particular setup.
6/ Restart your web server to pick up the new group permission:
$ sudo service apache2 restart
The interesting thing here is the setgid bit on those directories will cause new files created in the directories to have the same group by default. This means you don’t need 777 permissions—which means you have more security as well as a system that should continue to work.
The umask part is also important. New files will have the permission bits in the umask stripped, so if your umask is 022, the new files will not be group writable, and things won't work very well.
I've been using this setup very successfully for a number of years now.
/var/log/apache2/error.log?