I run Gaytube.com (NSFW - adult content), We have been working with Social Media as a redesign solution, and have been very pleased thus far.
Customer support is extremely friendly, and more than accommodating when requesting mods.
It's easy to set up, flexible, fast, has the ability to add commercials, and has a great flash player.
The only two drawbacks are that some modding needs to be done to handle high traffic volume, and may be difficult to edit if you dont have php/mysql knowledge. :)