I watch a lot of movies as well and have been purchasing most of my movies for the past ten years (I've got a pretty big collection). A couple months back when I reorganized my game room for my Kinect purchase, I realized that a decent portion of my collection I had no intention of ever watching again. I was just wasting money and shelf space on a bunch of one watch movies. So I decided to give Netflix a shot.
So far, I am fairly satisfied with my decision. The best part is the back catalog of TV shows. My wife and I have been wanting to watch True Blood for a while but didn't want to start in the middle. By being able to get the first two seasons on Blu-Ray from Nextlix saved me $100 alone. I personally don't watch TV epsisodes more than once (Outside of Family Guy), so the TV episodes are a great selling point for me.
The streaming movie selection is ok. There is a decent amount of classic movies and a fair amount of recent movies...but most of the recent stuff I already own so it doesn't do much for me. The best part of the streaming movies is a lot of the lower budget and limited release movies you might of missed are available to stream...so you didn't waste any money purchasing a lousy movie. It's also nice for kids as my daughter can watch Care Bears and other cartoons as well. If your into Anime, there is a decent selection to stream as well. In the end, it's nice if you're bored and need something to watch, but as it stands right now, I wouldn't sign up for the Streaming Only service.
The disc based service works really well. Most new releases trail by about a month from their retail release. Once you take yourself out of the purchasing loop for a month, you'll have plenty of new movies to watch. Delivery is prompt on movies. I put one in the mail on Monday, I'll have a new movie on Wednesday. It's pretty awesome.
I still find myself purchasing the bigger release movies that I want to add to my collection. But in the end, subscribing to Netflix is well the worth the money and I plan on keeping it for the foreseeable future.
Also, just try the trial and don't worry about using your card online. All credit cards are protected by the issuing company and the most you can get stuck for is $50 if you ever get fraudulent charges on your card. Just be smart with who you purchase things from and keep your computer security up to date and you should never have a problem.