Short version: If you liked the book, you'll like the movie.
Long version: First, I owe my boss a huge thanks for being organized and planning ahead. If it were up to me we'd have been lucky to get tickets and probably wouldn't even have been able to sit together. She had this all mapped out. Leave work around 5, find parking, pick up our tickets, head across the street for appetizers and a drink, and be in line by 6:30. You'd think that I would have learned after she was right about needing to buy tickets on Monday, but I didn't. I was pretty sure we'd be standing there alone at 6:30 looking like fools. Fools who were really too old to be seeing Twilight. Well, I was wrong. There was already a very long line at 6:30, and getting in it when we did was the only reason we got decent seats together. A few observations...teenage girls really do talk a LOT, and now they all have cell phones so they can call and text each other constantly. Also, they all wear Uggs. Now, it was ridiculously cold out for November today, and it did snow a little bit this morning, but I do not know what the deal is with all the Uggs. Or how such young girls can afford them.
On to the movie. They stayed very close to the book, which I think is an important factor. Robert Pattinson is perfect (and hot!) as Edward, and Kristen Stewart makes an excellent Bella. They have a nice chemistry between them, which makes the story believable. Well, you know, for a vampire story. Some of the supporting characters aren't quite as I imagined them, but it's really Bella and Edward's story anyway, so it didn't really bother me. I did like the actress who plays Alice quite a bit. Forks is just as I pictured it would be, and I do love the Pacific Northwest. The scenery in the movie is gorgeous.
Overall, I loved it. The movie is a little slow to get started, but so was the book. Once Bella and Edward start interacting, it gets interesting. The movie is two hours long, but the time just flies by. One minute they were just meeting in biology class (and Edward was being so very rude), and then all of the sudden we were at the part with the showdown with James. I suppose it helped that I knew the story.
I usually avoid theaters on opening nights, so I had no idea how much fun it would be. When the lights first went down, people started clapping. When favorite characters first showed up, people cheered. When the bad guys turned up, you could feel the tension in the theater. And just before certain particularly romantic moments, you'd hear people shushing their friends. I had a blast. And I'll say again, if you liked the books, I'm sure you'll like the movie. If you haven't read them, well, it is a good story, if you like romantic vampire stories.
In conclusion, my inner teenager would like to add "Twilight! Squee!"

I'm heading out to see it on Wednesday and I can't wait...I have to echo the teenage "SQUEE" because that's pretty much how I feel about the anticipation!
Glad to hear that you loved it!