If it were me, I'd replace the monk with either a fighter or a Valkirie for more front-line power. I haven't played either a monk or a ninja yet, but they appear to both be the type of class that if you manage them right, will be weak in the early game, but pretty awsome in the late game. Of course, usually with clases like these, if you manage them wrong, they will suck eggs.
My Current party is:
2 Dracon fighters
Mook Ranger
Halfling Bard
Rawulf Priest
Elf Mage
I've just started again using this line-up,so can't tell you much about it yet, except I think it will be pretty balanced.