5. Monster Squad: I still haven't seen the original, but like Goonies and Adventures in Babysitting and that ilk, I think the largest obstacle to a remake is having a group of prepubescents running around city streets late at night, using bad language, and making crude sexual references. That's how 80s kids behaved (speaking as one), but how many Generation Y helicopter parents will let their children see it? They had to set Super 8 in the 70s to make it believable.
4. Harry Potter: Given the unprecedented amount of influence J. K. Rowling had over the production of those films, I wouldn't be surprised if there was a clause reverting the film rights back to her soon. But in any event: the films have proven people were willing to sit through 8 2+ hour adaptations of the books--why wouldn't they think they could make that kind of bank again?
3. Gargoyles: Sure, why not?
2. Babylon 5: FUCK YEAH, Babylon 5. My concerns are that much as diehard fans like us would like to think, it wasn't popular enough. And would its 1960s-era optimistic idealism really fly in the current culture? This would need a really lucky break like the BSG reboot to get off the ground.
1. Simpsons: Not seeing it, personally.