Allison Cameron works in the ER. She's much happier there than she was as a member of House's team, though she returns to the latter early in season six.
Added:
Cameron pleads with House not to ask a patient to essentially kill himself in this scene from "Simple Explanation." The main storyline of the hour, however, was Kutner's suicide.
Added:
Here's a shot of Chase and Cameron from season three of House. They haven't exactly received a lot of screen time since then.
Added:
Cameron took over Cuddy's job for the episode titled "Big Baby." This change didn't last long, however.
Added:
On House, Dr. Cameron is often the voice of reason. She's played by actress Jennifer Morrison.
Added:

House Quotes

I don't want you to change. I know you're screwed up. I know you are always gonna be screwed up. But you're the most incredible man I've ever known. You are always gonna be... the most incredible man I have ever known. So unless you're breaking up with me, I'm going home now.

Dr. Cuddy

People don't get what they deserve. They just get what they get. There's nothing any of us can do about it.

House