Half of the time, they're pretty damn realistic, to the point where I can't tell it's a dream, but seems so real. Other times, I realize I'm dreaming, and I take advantage. And I usually do remember them, although every one in a while, a dream will occur and I won't remember exactly what happened. That usually drives me insane.
The last dream I had.. was pretty upsetting, actually. I only remember the last part before I woke up, but it was similar to the episode of House where Amber dies. I was strapped to life support in a hospital, and out of all the people who were there, it was Batista, the former WWE wrestler, along with someone else from WWE who I don't remember. It was pretty touching, as they were about to put my off life support. The most vivid part of the dream, though was where I died. All it was was my thoughts, Everything was pitch black, but I was conscious.... yikes, this is giving me the creeps.