I've never screamed at this movie.
I would quite like to see Scream 4. Though I am glad the pirating whores haven't released a good quality download yet. I like to pay for my movies.
Scream 1 is the best one by a mile, at the time it was a breath of fresh air in the horror genre and that opening scene with Drew Barrymore still gives me shivers everytime I watch it. It's horrifying.
Scream 2 was very good. Scream 3 was more cheesier but I liked the way it tied everything together and revealed things you didn't even know existed.
Scream 4 was decent enough. It didn't scare me once, it was quite predictable and there was actually points where I was laughing out loud.
At appropriate times? The Scream movies have always had an element of humour in them. If the "scary" parts are causing you to giggle, though, that is generally not a good thing.
I watched the Trilogy last night, Scream 1 is by far and away the best. Scream 2 was OK, Scream 3 was ridiculously stupid.