I hated Megaton in fallout 3, the first time I blew it up only to have the game be a real hard pain in the ass after that. So the 2nd time I didn't blow it up I saved it but got attacked for stealing food to save my life so I ended up wiping out the town once again.
I really enjoyed the option of saving an entire town or destroying it, I know in all of the fallout games you can choose to kill or spare people which effects your karma, which is my favorite thing about the game plus the alternate endings.
But how about for future games there are more towns like Megaton, towns that you can save or choose to destroy. It makes the experience much for intense.