I mainly buy and sell in person. Email is generally kept minimal, if I'm shopping I message the seller and say I'm interested in the game and ask if it's still available and when are they available to show it? I try to act quick, if it's a deal I'm hopping in my truck and heading there as soon as possible. If it's not a deal, I still try to set it up for within a day or two so it doesn't get sold before I can check it out.
All discussion about condition and price haggling should happen in person IMHO. When I sell games, I hate taking deposits or holding a game for the first person. I used to be OK with it, but experience has taught me most of these people will flake or drag out the transaction forever. Nothing like holding a game for a week or two for someone and then they back out. One guy put a deposit on my game and then took no action on it for months. He was out of state, eventually he paid and arranged for a shipper, but that was a huge hassle in itself. When I'm selling a game I generally need the space and cash for another game coming in, I don't want to store it for weeks or months for someone.