Warlock
Rogue
Rogue
Sorcerer
Someone else posted the wilderness group, this is my urban crew. Stand up fights are for those too stupid or too unprepared to find a better way.
Warlock - Faceman, high charisma, decent int and dex. Bluff, Disguise, and intimidate. Take charm plus any utility powers (Walk Unseen, Flee the Scene, for getting in and out, Baleful Utterance for taking out locks and doors, Beguiling Influence for face skills)
Sorcerer - Some combat spells for emergencies, as well as access to things like teleport, fly, and the more standard arcane spells.
Rogue + Rogue - The heavy lifters of the party, they do the dirty work, as well as act as the main combatants. Surpise, flanking, and sneakattacks should cut down anyone fast. Expect them to go into Nightsong Enforcer and Nightsong Infiltrator.