I like Rose & Crown (I think that's what a previous poster had mentioned) but it's all a matter of luck. I'd try to make your reservation for between 7:15 and 7:30. We've never been seated right away, so you'll probably have to wait, but be sure to request a "lagoonside table" (below the patio). Officially, they don't take requests but it never hurts to throw in a request when you check in. If you're celebrating something (i.e. birthday, anniversary, personal triumph), mention that as well. Nothing's guaranteed but most tables offer very good views, but those right next to the lagoon offer views that cannot be beat.
As for how loud IllumiNations is, it's very loud. To quote Jim Hill, "No, they did not just blow up the theme park. That was just the fireworks."