Girls with tattoos and glasses. In games? Dungeons. With loot. Where I can go back, if I want, just to make sure I got all the loot. Don't close paths off to me, if there's collectibles. I want to be able to go there again and again and again, go down paths all the way to dead ends, then come back, and go down the next dead end. I want all the loot.
And if the merchants have an unlimited currency dispenser to appropriately accommodate my looting, we have near perfection. I'm loving Skyrim, but having to waddle from town to town to hawk all this stuff drives me nuts. And that I shouldn't pick everything up and then sell it also drives me crazy. Having to choose between all of this stuff makes me a sad panda.
But, having the freedom to return, pick up all the good stuff, then go hawk it later makes me happy again.