I know that this has been done to death, but what they hey?
My votes - Dances With Wolves - that was embarrassing
Forrest Gump - quite possibly the most annoying movie ever made
Gladiator - just didn’t like it
Titanic - Harlequin romance at sea - Fortunately DeCaprio’s career has taken quite the nose dive since 
There is a story in the NY Times on this very topic.
I haven’t seen any of these but some of the candidates include “Cimarron”, “Cavalcade”, and “Around the World in 80 Days”.
Actually I have seen “Around the World …”
It’s not that great.
My pet peeve has always been Rocky. Condider the other nominees that year (1976): Network, All the President’s Men, Taxi Driver ! I mean the original Rocky was OK, but come on!
Gladiator
Greatest Show on Earth
Rocky
Titanic
The Washington Post also did an article on this same topic. One writer’s choices included Titanic, Deer Hunter, My Fair Lady, Around the World in 80 Days, and (at the top of his list!) Gone With the Wind.
The other writer proffers The Greatest Show on Earth, Cimarron, Gladiator, Going My Way, and Forrest Gump.
I’d have to agree with Titanic or My Fair Lady.
There may be worse Best Pictures that I haven’t seen. But of the ones I HAVE seen, theworst are:
Of the films I’ve seen:
Gladiator - Not impressed. Standard action fare, good summer movie, not Best Picture.
American Beauty - This one will get me yelled at, I’m sure, but no matter how many times I’m told this is a good film, I cannot see what was so good about it. It was a cliche-fest with the acting being the only redeemable quality, IMO. I think also-rans The Insider, The Cider House Rules, or even The Sixth Sense would have been better picks.
Titanic - My dislike of this fillm is well-documented around the boards. By the numbers plot, cardboard characters, at best mediocre dialogue. Personally, I thought LA Confidential was the Best Picture for this year.
Rocky - This has been covered already.
Tom Jones - Not impressed in this one at all. I thought it was one of the unfunniest comedies I ever saw.
West Side Story - Just a personal thing here, but I hate this movie. I hate the music. I hate the concept of the dancing street gangs. I hate it, hate it, hate it.
Around the World in 80 Days - This beat out Giant, The King and I, and The Ten Commandments?
Marty - I’m sorry, this one just failed to impress me in any way. On top of which it won although one of my favorite films, Mr. Roberts, was also nominated that year so I may just be a little biased here.
While I was less than impressed with Titanic, a very popular target for the topic, I can sort of understand why it was so well-received by others.
Gladiator’s popularity and raves just confuse me. I enjoyed seeing it, sure, but…ah well. Life wouldn’t be life without these kinds of mysteries.
“Annie Hall” - zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
Titanic is on TV here in Ireland as I write. It may be an atrocious movie, but that ship sinking scene is utterly jawdropping (and you get to see Kate Winslet’s babylons).
…and the added bonus of Leo dying a cold, painful death!
Out of Africa was astoundingly dull. How it won, I have no idea.
But the winner I’ve seen that mystifies me most is Gigi. I mean, the songs were good, but the movie as a whole was just “eh”.
Gladiator: There’s no reason this should have gotten BP considering what it was up against.
Titanic: Feh.
Shakespeare In Love: I say again: Feh.
Nobody’s yet mentioned The English Patient? Put me to sleep.
Let’s not forget Oliver!. Hate, hate, hate musicals.
BTW, a list of Best Picture winners is here.
My reaction to the film: “Jesus, dude! Will you die already???”
What about The Forbidden Zone with Danny Elfman and Herve Villachiez? 
(Okay, it didn’t win an Oscar, but I loved it!)
Midnight Cowboy
I agree. I rented this a couple of years ago to see what the big deal was. After all, it originally had an X rating!
Egads, did it suck!
It IS a good example to see method acting acting at its worst. Dustin, I’m looking right at you!
Out of Africa. I’ve seen other ‘White man tames Africa’ films better than this tripe, such as Tarzan. And I really hate Tarzan and the concept itself.