Do you describe your characters when you write?
I'm on the fence about this. On the one hand, I hate it when I have an image in my mind of what a character looks like, say a tall but chubby blond with green eyes, and then the author throws in a description of that character as a short pixie-ish brunette with sparkling blue eyes. It throws me right out of the story. Usually this is off-set by a description of a character early on, such as Harry Potter with black hair, green eyes, and round glasses. I'll never picture him as anything else.
But there are still pitfalls to character description. For example, I never pictures Malfoy as the way Rowling described him. In my mind, despite her descriptions in text, he was dark and brooding (more like Krum). It wasn't until the movies that I even realized I'd supplanted the author's vision for my own. His character just didn't fit his description to me.
And what's more--if the main character is a girl who acts a bit like me...then I want to picture myself as the heroine. It drives me crazy when the physical description is nothing like what I had in my head.
To counter this, I purposefully did not describe the main character in my first two manuscripts. No one has ever commented about the lack of description on one of them, but many people have commented about the lack of description in the other. In fact, I had an agent reject that manuscript based entirely on the fact that he felt as if he didn't know the main character and he wrote specifically that a character description would have helped with that.
Do you give specific character descriptions? On the one hand, I can see the advantage: Harry Potter is an icon in part because of his description. On the other hand, sometimes it limits the reader's imagination. Where do you stand?