Star Wars would win. It is much more powerful. Only the flood could win. Death star would wreck all things. Also that... Weapon that can destroy stars....? Can't remember it's name. I love Halo but it is not as fantastic as Star Wars. The flood uses it's food as it's strength so if it was allowed even one foothold on a planet then it could spread through out the star wars universe and win. Though droids would still exist I guess and drink cocktails with the flood.