in 'Hitchhikers Guide' we were invaded and ruled (?) by highly intelligent mice, as well as dolphins (so long, and thanks for all the fish) who experimented on us. I think the backstory of 'Battlefield Earth' is that earth had been conquered (I wasn't one of the 203 people to watch it).
I think the story of earth-under-alien-dominance is potentially intriguing, but not made for two hours of action and explosions, which is what our media, esp our movies, specialize in. ('Earth Rebels from Evil Alien Control' is a viable concept.)
concepts worth considering; would our governments cooperate with Alien Overlords? would there be an organized resistance (after the posession)? What would the AOs want? slave labor? food? resources? build a base for ongoing war with other aliens? Purge the galaxy of rap, metal and reality shows?
one more thought; history shows that outside invaders are frequently helped by disgruntled insiders, most notably the Meso-Americans who cooperated with Cortez and other conquistadors to overthrow the hated Inca/Aztec overlords. would disgruntled Terrans aide and assist alien invaders on idealogical grounds, not to mention pure hatred?
imagine the potential of an intelligent alien race using their technology to convince Muslims that the Mahdi is coming and 'encouraging' the faithful to 'pave the way'.