Another voice towards high op characters in a low op world. Only in my case, its by accident, I try to cripple them and drag them down to the level of the rest of my group (on those rare occasions I play D&D), but I can't. And this is from optimizing defense and playing front liners, which only works because the DM never uses the kind of tactics that make it hard to resist. My group finds good saves, high AC, and a decent miss chance more palatable than an offensive monster, and are fine with me using highly defensive options for near invulnerability, but then battles take forever. And I'm not even that good at optimization, the guys I'm playing have no right to be above anyone in power.

Of course, the fact that half of my group has little interest in role playing is a bigger problem, but that is slowly changing, and most of my gaming is done over Skype or chat with people who are die hard role players now anyways, so no harm done.