I've been a forever fan of ProjectFree.tv. You can watch full length movies and tv shows for free. They can get away with it because the site itself doesn't host the stuff, they just provide links to sites that do ;)
However, sometimes I've found that none of the links might work, or in some cases, they are under construction or might just be too old or too new to be in their database.
So I decided to search online for other sites similar to ProjectFree.tv ... sites that were safe, and yeah, had ads, but for the most part were manageable and had good quality streams. A couple of these do ask for a one time fee, but with the whole LimeWire shutdown, and FrostWire not being reliable AT ALL, I've been known to pay a fee here or there, especially if the downloads are great quality.
1 year unlimited for around $40, 3 months for $35, or 1 month for $30. They have the biggest movie database in my opinion, and I like that it's not a peer to peer service, like LimeWire. I paid for 1 month during summer while the kids were at camp, and I was quite happy with it. Downloads were super quick, and I was easily able to convert the files and burn them onto DVDs.
They do send you a lot of emails, but it's simple to add them to your spam folder :)
This site is just like Full Movies, except the one feature that offers a plan for 2 years for $40. This is an awesome deal, and they obviously want you to buy that since the other plans are the usual 3 months for $35, or 1 month for $30. They have a good database, but I wasn't able to find really obscure movie (like Brick or The Christmas Toy). Overall I was pretty happy when I had it, and to top it off they pretty much leave you alone on the email front.
This is the same as MoviesCapital pretty much. Offer you the same awesome 2 year plan, except that their movies are compatible on all MP4 players, IPods, IPhones, PSPs, and smartphones. They also hook you up by giving you tools to burn your movie downloads to DVD in case you're not sure how to do that. This one I haven't personally subscribed to, but probably will in the future, since it's not a peer to peer either.
There are some more that are similar: