Only a dolt thinks that Charisma has no effect, even in a hack-and-slash game. If used effectively, social skills have an incredible effect on combats.
The group is the same as outlined previously...
Just yesterday, we had the climactic battle, but things weren't going too well. I managed to charm the enemy rogue (and used a charisma check to get her to attack the enemy cleric number 2). But unfortunately, the evil minions coupled with the number 1 bad guy (another evil cleric) managed to take her down. We managed to take out the minions, and then, badly wounded, down to 2PCs (we were facing a Nerull cult, so they Death Knelled our party rogue) and faced with the big boss, unharmed, scythe-wielding, death knelled, enduranced and angry, we knew we would lose. So, combining Bluff, Intimidate and a quick prayer, I declared: 'We have defeated your minions and you are now outnumbered two-to-one. I suggest that you stands down immediately, unless you wish to end up like your apprentice'. I then coup de graced the apprentice cleric. Nevertheless, he gave us a cursory glance to try to determine how badly wounded we were. Another Bluff success told him that we were fighting-fit. Downing a potion of gaseous form, he retreated out of the manor.
We gave chase. I managed to climb out of the window with my comrade holding the rope, and he took the stairs. Downstairs, he encountered some more guards. He would almost certainly have been killed in his wounded state, but he bellowed 'We have defeated your master. Flee now and I will spare your lives.' They ran. Meanwhile, the gaseous master had entered the library and I went in smashing the downstairs window. Unfortunately, he had hidden and managed to surprise me. Luckily he missed, but what happened then was a curious cat-and-mouse chase. I dared not run away lest I draw a fatal attack of opportunity, but in his full plate he could only run 60', so I could safely double-move away. I also knew reinforcements were on the way, in the form of the charisma 3 barbarian who had failed to originally infiltrate the building. Inside, two more guards had approached my colleague, and though he intimidated one the other held his ground and in a quick clash the player only just triumphed with 2hps remaining.
Outside, the guards whom had fled from inside saw their master pursuing me and joined in the chase. In lighter armour, they could reach me. I chose to break into a run to avoid them, but as suspected, the AoO from the master hit, reducing me to precisely 0hp. I was forced instead to drink a potion instead of go the distance. The master then offered me a surrender (with a less charismatic character, the DM confided, he would instead have pressed the attack). Bluffing again, I presented to surrender but then broke into a run. I managed to escape and fled to meet the oncoming barbarian. The barbarian slew the minions before being killed by the master. However, the party cleric had run up from the house by now and together we Intimidated the archvillain, still knowing that he could defeat us, whilst bluffing that we were less wounded than we really were. Running out of options, he decided to run to a distant gatehouse controlled by his troops. Drawing our missile weapons, we eventually killed him in a drawn-out pursuit.
A long-winded anecdote perhaps, but it demonstrates the value of Charisma. No less than eight Charisma based checks were involved (the charmed rogue, the initial intimidation, the bluff to demonstrate health, two sets of intimidations against the guards downstairs, the bluff of surrender, the final intimidation and bluff) and a passive Charisma check (offering surrender terms instead of killing me) turned a total player kill into a victory over a much stronger foe. Now who would claim that Charisma, well-deployed, has no place in a combat?