A cleric route is probably the strongest (anything with full casting generally is).
Ghost savage progression is pretty strong, but can potentially unbalance a game at early levels and/or make things very difficult for your DM.
I would pass on monk. You're already sucking up LA+2, so taking a medium BAB and trying to flurry means your attack bonus will be so low that you won't hit anything.
An interesting route could be to go barbarian with the berserker strength variant from Player's Handbook 2. Since you enter beserk state when your health is below 5*barbarian level, with undead d12 and no con bonus, you're pretty close to a beserk state at all times. Take the lion totem substitution (Complete Champion) to get pounce for all your natural weapons. If you'd like to get some speed back, there's the Fangshield sub (Champions of Valor) which trades trap sense for +10 speed when charging.