Real world scale. If it is 3 meters tall, then make it 3 meters tall in your model program. This will also allow you consistency in all your modeling, and you will know that everything is the size it is supposed to be.
Characters tend to be scaled down to 80% of normal. The camera view of the player appears to be around 6'5" instead of 5'8 to 5'10".
Door width minimal is 42" wide and 8ft tall to allow a standard human character to be able to pass thru it.
Weather you are using feet or meter, just keep it real. also works more consistent in the editor when you actually need to scale it up or down.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit
