Don't think it makes sense to turn this off for a single worker and it's on by default.
The docs indicate that Nginx will use the best method based on the available methods
Keepalive of 5 seems very low - i've seen recommendations of 10-20
gzip_proxied was set twice
gzip_static should be off unless actually used
default is deprecated
server_name _; shouldn't be used
Shoudn't use expires in the server {} block - should be inside location {}
Extra root lines not needed
gzip_comp_level seems too low
gzip_min_length seems too high
Add text/x-component. It's listed in html5-boilerplate/.htaccess and is in our nginx-mime.types
Fix application/xml+rss, should be application/rss+xml
Comment indicating text/html is always compressed, so there's no need to include it
sean