Having done the floors in a few houses I've owned, this is what I have to gleen. The final color of the wood floor will affect the overall brightness of the room. A light natural wood will make the room brighter and larger, a darker wood will make the room darker and smaller. Certain types of rooms do well with a darker more elegant look, (ie formal dining room) and lighter wood enhances rooms you want to have a bright feel. Stain basically creates a uniform look to the wood. Clear allows each peice of wood to show its difference.
Also, after you get it down, fill the room with a few rugs and furniture, the floor will become secondary to the rooms decore and furishings. A dark floor adds to a light rug and a light floor adds to a dark rug. Enjoy and good luck. (I always found picking out the final stain and finishes was the hardest part for me)