Which do you prefer in shooters? The Keyboard/Mouse or a Controller?

Like the topic title says, which is your preferred method of control in shooters of any kind? I'm a huge keyboard fan, but that comes from playing Quake III/Open Arena/Elite Force 1 or 2, and Call of Duty, because those games are very fast-paced and require lightning fast, accurate turning speeds. However, in Halo or other console-based shooters where character movement is significantly slower, the keyboard and mouse is almost nigh on cheating and somewhat uncomfortable, so I stick to a nice ergonomic controller in that case. xD

So, what about you guys? =P

I don't have much experience with shooters (not my preferred genre of game), but I very much prefer the keyboard/mouse approach. Using a second analog stick to aim and a shoulder button to shoot seems... bad. It takes a considerable amount more concentration to aim and shoot that way than with a point and click.