If you get into trouble with being locked out of logging into WordPress or delete your .htaccess by mistake this is the current default .htaccess
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
There are many other options for sub domains and mulitsite installations here.