I want someone who is capable (and has the courage to) of recognizing and getting rid of the deadwood. These people are harming the product and slowing down the completion, get them out of my way! All too many managers either can't recognize who is a bad developer (or think the one with the messy desk is bad or the guy who appears to be starting off into space alot even though he may actually be the smartest or most productive dev) or don't want to have to be the one to tell someone they are being let go and so let the deadwood stay year after year causing harm and discontent among the competent.
I don't want to be embarrased by a manager who doesn't even know what languages or database backend or other critical tools we use. I had one ask (in front of the client)what language we programmed in after being involved in the project for 3 years! I don't expect people who have been in management a long time to still be current on the hows of everything, but they should at least know what are we using. And they should be smart enough not to ask stuff like that in front of others if they don't.
I want a manager who has courage. Don't accept that unrealistic deadline without pushing back, don't let people bully your employees or let rouge developers go along their meery way without being brought up short. Don't fail to tell me if I am doing something wrong because you are afraid I might get upset. Managers exist in part to handle the bad news, I want one who can.
I want a manager who understands I have a home life, who understands that exhausted devs make mistakes and it takes longer to do a project working 60 hours a week than 40.
Most of all I want a manager who recognizes good work and is verbally appreciative both to me in person and up the chain to his or her bosses. Although I really hate it when they think the bad work is good work and reward the wrong people!