Agreed.  For PC games, none was ever a bigger disappointment than MOO3.  Rome Total War comes in second, although at least that one still has some charm & appeal -- MOO3 was simply broken. 

As for movies, I agree with greenpower's mention of Matrix Revolutions and The Phantom Menace.  (I would also add Attack of the Clones, as the writing/dialogue is about as craptacular as it comes.) 

I didn't find Star Trek Insurrection so horrible, but Nemesis (the 10th movie) sucked *hard*.  Only the first Trek film (The Motion Picture) was worse IMHO. 

I agree that the Star Trek sequels II, III, and IV were all better than the first one.

Some awful sequels: Beverly Hills Cop 3 & Windows ME

robocop 3

Penitentiary 2.

Must be seen to be believed

Definitely Master of Orion 3. And the film.... I would say The Mummy Returns.

I'm for...

Ocean's 12 (although 13 is better)

Son of the Mask

At Worlds End

Star Trek V

As for the infamous Phantom Menace, as far as I'm concerned it wouldn't have been too bad if a. no Jar Jar, b. better actor for Anakin (the bit when he's in the space battle ruins the rest of the film) and c. less dawdling on Tatooine (where nothing happens for about half an hour except a pointless race)

As for games, I think this game deserves an inclusion - here's the review of Seven Kingdoms - Conquest: http://uk.pc.gamespy.com/pc/seven-kingdoms-conquest/867913p1.html

They don't have to be bad movies, just bad sequels.

For me it was Predator 2.  I really liked Predator the original starring not one but 2 future governors.  Predator 2 just can't compare to the suspense of the first one.

As for software it's Empire Earth III.  Just does not measure up to the first 2 and, as I understand it, they're not going to release any updates or expansions for it.  It's a dog.

Definetely Land Before Time XVII (17)

Really, did they really need to bring Big-foot back with Pimpin-Joe Triceratops as his sidekick?  At least they got rid of his hoes this time, unlike XIIV and XVI.

Did they need to make more than 1? Much less 17 >.> I remember watching maybe two or three. God those movies were odd.

To be honest, I googled and it tuns out there's around 12 (at least it was last year)

The first movie was decent, than the rest where the radiocactive byproduct of the chernobyle accident.