When I was in college, a mini-series called "V" was made-- it stood for Visitors, aliens who came to Earth claiming they wanted to help us. It was a decent-enough miniseries which ended in a totally hokey way, and was then made into a forgettable TV series.
The premise wasn't bad, though it could have used work. So why not do that work (in these days of Battlestar and Doctor Who and Trek)? Surprise!
Spoilers for the original series:
In the old show, the aliens were actually lizards wearing fake human skin, which is maybe really silly, since it was never clear why the fake human skin hid the actual shape of their decidedly reptilian heads. The aliens came here to steal our water -- dumb, since there's a LOT of water in space in the form of comet nuclei which are a lot easier to get to -- and to eat us -- also dumb, since the likelihood of aliens being able to ingest our proteins without poisoning themselves is really really low.
Plus, they came from Sirius, a star very unlikely to have habitable planets; the primary star is orbited by a white dwarf that would make it hard to have stable orbits at the right distance... plus the star that formed the white dwarf must have gone through a red giant phase that would've wreaked havoc on the system. I am an optimist when it comes to habitable planets, and even I find it hard to look toward Sirius as a potential nursery for life.
The worst part was that an alien male and a human female had sex and she got pregnant. Um. Really? A friend of mine in school at the time didn't see any problem with that, and I asked her if having sex with an iguana was likely to result in a pregnancy.
And don't even get me started on the hybrid baby that glowed with sparkly thingies and has psychokinesis and could land the big ship at the final dramatic moment so that the day was saved.
Still. I'll watch, Why? Aliens, spaceships, and Morena Baccarin? C'mon, I'm only human!