normal/medium thinking to myself that I'll want to play it on a harder difficulty a second time but than never do. Ive been doing it for years.....very few games have I played the campaign over....
Normal but after that it depends on the game. For example Fallout 3 I can hack it at a higher level while Dragon Age Origins I play on casual as I hate micromanaging things every battle.
To answer the OP's question, it depends on the type of game. Most action/adventure games I do on the hardest mode off the bat, guitar hero/rockbands it's expert everytime, but world-builder's like Civilization and Warcraft i rock normal. Oh and FPS games are lame if they aren't on the hardest mode!