The worst movie hasn't been released yet. I was just reading the cast list for it though...
http://www.imdb.com/title/tt0460780/.
Not a bad cast but the best actors in the world couldn't save this project. When Tarentino did Kill Bill in two volumes people were skeptical but it turned out ok because it was Tarentino... Uwe Boll shouldn't be allowed to even try.
I would say of the current movies though Island of the Dead was MUCH worse than House of the Dead. Flies!? C'mon!!!