Time of the Apes
Amazing Colossal Man
Santa Claus vs. the Martians
Hercules vs. the Moon Men
Jack Frost
most of the Gamera movies
Viking Women and Sea Serpent (with the Home Economics short)
Teenagers from Outer Space
One classic is War of the Colossal Beast (the unnecessary sequel to The Amazing Colossal Man). It includes the truly bizarre short "Mr. B Natural", starring Betty Luster in the title role. As Dr. Forrester says, it is a "nightmare from the heart of whiteness."
My favorite episode is "Fire Maidens of Outer Space," but it's not for everyone. Crow wails at the end, "Cy Roth had to pad the film just so he could get to the parts that had more padding." But the long spaces with no dialogue allow the guys to basically make up their own scenes at times.

The Day The Earth Froze was good, but unfortunately hasn't been DVDificated yet.

I remember one from long ago with giant ants or grasshoppers, it was several years ago so I don't remember the name but I'm sure someone does, also don't forget about "Danger, Death Ray".

Beginning Of The End
There's naturally quite a bit of attack of the giant whatever in MST3K. Leeches, shrews, gila monsters, spiders, teenagers...

Don't forget 'The Deadly Mantis' either.
I've got a mantis in my pantis.

Oh, seeing Krankor there reminds me that both Prince of Space and Invasion of the Neptune Men are good. Krankor, you've got to change your title to Phantom or something. Or maybe "Ba-KAW!"

:D Seeing this gave me a good laugh this morning.

Man, I always read what you have to say extra carefully, purely because of your screen name! :)

"Mitchell- Heart poundin' veins cloggin'"
Mitchell > all other episodes of MST3K...

Mystery Science Theater 3000 (MST3K): Gumby in Robot Rumpus
http://www.youtube.com/watch?v=3M4_XZ3FLHw&feature=fvw

I started watching Space Mutiny last night.
I should have used "FLINT IRONSTAFF" as my alias. Or maybe "THICK MCRUNFAST"

Extremely hit or miss. As much as I like the show when it's at its best, I've seen more bad episodes than good ones.
Time Chasers and Space Mutiny come to mind as being out-and-out hilarious, as well as many of the shorts and PSAs they cover, but many of the movies they pick are just so crushingly dull that the crew can't wring much life out of them (Hellcats comes to mind).
The Manos episode is overrated, I think. As I recall, it was funny, but not that funny.
Also, I just skip the intermission sketches. I realize they're supposed to be cheesy, but I just can't take it :p

The Manos episode was funny in some parts, but the movie itself is just boring. I doubt anyone could do much with material like that. And I agree with you, the intermission sketches are a bit too much for me. It's kind of strange, because the skits seem like something you'd find on a children's TV show, but the meat of the show, the riffing, is not something you'd be likely to show to your kids.
By the way, that Gumby short was really funny, and has restored my faith that Mitchell will be good, whenever it arrives.

I've got to admit that 'Manos' although regarded a classic, isn't one of my favs. Sure theres some funny moments, but the movie is so dull it does grind you down.
Space Mutiny (as previously mentioned) is an epic though. I love the scene where the communication officer gets killed (you know, the one with an Armadillo in her pants) but in the next scene shes back!
Some of the worst editing you'll ever see.
Chest Brockman!
As for Mitchell... you're in for a treat. Gotta luv the coughing and wheezing gags.