Are Extensions Damaging

When you link to a site is it better to link:

Like this:
http://www.battlefield-game.com/

Or like this:
http://www.battlefield-game.com/index.html

With the .html bit basicaly, is it damaging as it could duplicate that page in a way or are search engines smart enough to know different, I always get a different page rank for the domain and the index file.

 

You should always 301 redirect index.html to the .com with .htaccess

 

the shorter the better. i would go for http://www.battlefield-game.com/