The configuration on this website is Gallery2, WordPress and the WPG2 plugin to tie these together. I do not use an “official” WPG2 theme, but just a a widget capable theme (spotlight). The only manual changes I’ve done on the php files was to remove the gallery2 logo from the top of each page. I somehow remembered that this could be done, but could not find it and therefore I used the big hammer!
Mostly this works pretty nice, but it does appear that the server is a bit slow once in a while. I do not know if it is the MySQL db or if it is WordPress (does not look like it is gallery2).