I have a 10th level Wizard walking around with a Staff of Power right now. The party's fighter has Demon armor and their on a quest to retrieve the hand and eye of Vecna...and use them. Every member of the party has at least one major magical item and numerous medium and minor ones. The wizard is a necromancer and the cleric backs him up with similar powers and the party is slowly amassing an army of undead. Next we have the cohort chain going on at its max efficiency.
Why so overpowered? Their on a quest ordained by Vecna himself. The old lich is attempting to gather certain powerful artifacts to him (ie, his hand and eye; the regealia of evil (BOVD), the BOVD itself and several more plus a few of my own design) in an attempt to purge the world of all other religions except his cult.
You see, Vecna has discovered a way to get rid of the rest of the gods. There's a method to kill them. The Vashra discovered it centuries ago but have so far been unable to utilize it. So of course, they kept it a secret...so Vecna knows.

Vecna needs a band of mortals to kill the gods for him. Its that simple and seemed foolproof...until Olidammara found out.

He promptly told Heirounous. Now a band of paladins are rooting out hidden cultist cells and eliminating them.
Therefore, my party has raided the vaults for as much items as they could and have fled, leaving what they couldn't carry to be destroyed. Their enemies are as well equipped if not better so. Its going to be a helluva campaign.
Sorry to derail the thread.