I have a solo elven fighter/mage who dual wields Katana's/Bastard Swords/Long Swords.
I am messing around in watcher's keep and came along the Self Righteous Bastard Red Dragon Saladrex. I talked to him for a while then i decided to leave, little did he know that i was goin to kill him in a very short time.
I got right up next to him and cast time stop, then once it took effect i imediatly cast improved aclarity, then i paused and immedietly cast critical strike then paused and cast greater whirlwind using the foebane+5 and celestial fury i choped him up for about and average of 46 damage per hit ten times in one round and i had one dead dragon and some gold, and other treasure

That's pretty slick. Greater Whirlwind is, IMHO, the best special ability. Couple it with Time Stop, and you can produce massive damage.

You could use a vorpal weapon with that strategy as well for anything with high regeneration.

and there you have the reason why i wanted to dual class sarevok into a mage.... grand mastery in a greatsword, a +5 greatsword, stun and deathbringer attacks.....10 attacks per round... a potion of wisdom and limited wish.....