I don't like sandboxes. Some degree of player choice is fun and desirable, but I don't like feeling like the DM hasn't plotted out any sort of story. Above all I want to feel like a protagonist in a fantasy story, not a person who happens to live in a fantasy world.
I don't like houserules. The ones I tolerate are merely the ones that are small enough not to effect the overall structure of the game. Substantial, systematic houseruling ruins a game for me.
Regardless of whether I'm playing or DMing, I don't like it when players don't have control over their characters, including build and equipment. I think the game is most enjoyable and has the highest stakes when players are playing the character they most want to play out of all the characters they could possibly be playing.
I don't like relying on player skill rather than character skill for noncombat portions of the game. If it is possible to play someone stronger or faster than myself, it should be possible to play someone smarter or more charismatic than myself. If I want to play the wizard who is the smartest guy in the room, the system should give me a way to do that other than me actually being the smartest guy in the room.
I don't see "video gamey" as a pejorative. Video games are fun, and if D&D is going to draw inspiration from anywhere, Video games aren't a bad place to look.
I don't think powergaming is bad, except when taken to ridiculous extremes. I'm totally fine with a player trying to play the biggest badass he can. If a character makes combat unplayable, that's a problem. But anything short of that, I'm pretty okay with.
I like the Points of Light setting. Its my generic high fantasy campaign setting of choice, easily trumping Forgotten Realms, Greyhawk, Dragonlance, etc. for me.
I love minions and use them consistently and in large numbers, even at high levels. I have no problem with PCs mowing through them, given that that's why they exist.