Personally I am a bit torn on this one.
Gerrard, a true leader for his club, personally i think he was undermined by Terry at the world cup. If he is not injured he will be a key player in Euros. That been said cant see him doing a full 90mins tonight
Hart, got years ahead of him, a steady figure, very vocal, and a great pro, but I am not a fan of GK been captains
Parker, decent player, has captain experience, played under stress, but limited Euro and international experience
Ferdinand, Not fit enough and cant be certain to make Euros due to injuries
Terry, wont be cleared by FA for euros (think he has burnt his bridges)
Only other true contender for me would be Barry. Plays at highest standard at City, tons of experience in top flight football, gaining more European experience, plays along some serious characters at city. Boring bloke though