Ok I saw it again so now I remember some. Some of these have been mentioned and I don't care.
LOVED "A hobbit lay here!" I even LOOKED like that terrain! Hilarious!!!
"I had a nightmare that people weren't as taken by my trembly mannerisms as I think they are!!!" Hilarious. Seriously---WHY does she have THREE guys fighting over her?!?!? What planet is she on, and can I move there? If they fall in love with her instantly, I'll be surrounded by admirers.
One of my favorites was definitely "It kills me. It drives me upstate and buries my body!"

Man I wish I thought of that.
I love all the jokes about the halloween fetish, my favorites being "Now she'll meet a cute emo Frankenstein kid!" and "Now she meets and instantly falls in love with a Merman" SOOOO funny!
All the jokes about the pausing rocked: "Complete sentence?..... NO!" and "IT'S NOT THAT HARD!!!"
Plus: "It's my job to protect you. I got it on Monster.com"
Oh and the jokes about changing her. "I want you to change me." "Just potty train yourself!!"
Oh and I loved when we first saw the Werewolf--I loved the Neverending Story reference--he looked like that dog!! Though that dog was much better, unfortunately. These effects were terrible---embarrassingly so. It's 2010 people!
All the others mentioned were hilarious too. Great riff. I think the riffs are better when the movies are this bad, don't you? Can't wait til the next Twilight rifftrax!!