I have yet to ban anything for any of my groups. Before we play, I sit them down and tell them that anything they can do, the NPCs can do and that shenanigans won't happen unless the PCs use them first. I run fairly high-power games, so any self-nerfing that happens isn't all that extensive (most of my parties keep using shapechanging, wraithstrike, DMM, etc., the only one they forgo being disjunction), but I've found it works out better if you let the players choose what's "too much" as long as you can handle the consequences.
Agreed. My ban list is anything that requires Exhalted status. It imposes restrictions on the game world that I don't want. Beyond that, goose & gander.
There are some things I have changed, though--especially teleport. When teleporting to a location you can only port to a place you have actually been or studied an image specifically prepared for the purpose of guiding teleportation. (Such an image can only be prepared by someone capable of teleporting to the location in question.) You're free to teleport blindly to an x, y, z offset from your current location but this is realistically only useful for short-range work or else overland stuff. Scry/buff/teleport does not work offensively but it *DOES* work defensively--if you're in the bad guy's lair and he knows it he can scry/buff/teleport in because he knows his lair.