This is actually the latest version getting used by wordpress...

RewriteEngine On
RewriteBase BASE/

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteCond %{REQUEST_URI} ^.*/wp-admin$
RewriteRule ^(.+)$ $1/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

An amount it seem like in Nginx?

location / {
 root   /your/document/root;
 index  index.html index.htm index.php;
 if (!-e $request_filename) {
        rewrite ^.+/?(/wp-.*) $1 last;
        rewrite ^.+/?(/.*\.php)$ $1 last;
        rewrite ^(.+)$ /index.php?q=$1 last;
        }
 }

 location ~* ^.+\.(html|jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js)$
        {
        root /your/document/root;
        rewrite ^/.*(/wp-.*/.*\.(html|jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js))$ $1 last;

        rewrite ^.*/files/(.*(html|jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js))$/wp-includes/ms-files.php?file=$1 last;
        expires 30d;
        break;
        }