[TG1]

Well Ubisoft, Sony and Squaresoft are always in my mind as companies I would love to work for.
On the other hand, there are advantages to working for smaller companies, or even new companies (There is a bigger chance you will get noticed by the people at the top, and that you will have a bigger influence on how things are going to look like).
As of genres, RPG, action and horror are my most preferred, although atrategy games (both real time and turned based) and puzzle games would also be nice. The only genres I would probably won't like to work on are racing and sports.