Also, if I remember correctly, you can catch Clint Eastwood in one of those flicks you listed: "The Flying Mantis." I believe he has a tiny little role as an F-86 pilot who tries to shoot down the Mantis... Those 50's giant insect movies were great! I fondly remember one with giant scorpions destroying Mexico, but can't remember the title...
The Thing, a.k.a. The Thing from Another World, was a fantastic movie, considering it was one of the very first SF films. I also REALLY like the original Invasion of the Body Snatchers, which still gives me creeps when I watch it! It also has the VERY beautiful Dana Wynter, who was quite a talented actress. She was also very good in one of my favorite war movies: Sink the Bismarck!
And in the 90's category, I think you mean "Mars Attacks" not "Mars Invades!" I agree that was an AWESOME film, which I scored as a rare perfect 10. I have a whole new appreciate for Slim Whitman and Tom Jones after having watched that film. Definately Tim Burton's best film since the classic Pee Wee's Big Adventure. It's interesting how both 1996 movies Mars Attacks! and Independence Day were both heavily influnced by War of the Worlds; ID4 was almost a remake.
Thank you for mentioning "Road Warrior." Great film, made Mel Gibson a real movie star! Also a big fan of Galaxy Quest, but you really need to be a Trekkie to fully appreciate it!