Of course I'm going to tell you that these items actually belong in your vhost.conf file(s), but just in case you don't have access to that, but your host does have mod_pagespeed enabled, here's the configuration I have running (very!) successfully with my Drupal 7 installation. In conjunction with CloudFlare, I've dropped my page loads by over 70% (almost 11s to 3s on average).
<IfModule pagespeed_module>
AddOutputFilterByType MOD_PAGESPEED_OUTPUT_FILTER text/html
ModPagespeed on
ModPagespeedLowercaseHtmlNames on
ModPagespeedEnableFilters extend_cache
ModPagespeedEnableFilters insert_dns_prefetch
#
# Text / HTML
#
ModPagespeedEnableFilters collapse_whitespace
ModPagespeedEnableFilters convert_meta_tags
ModPagespeedEnableFilters remove_comments
ModPagespeedEnableFilters collapse_whitespace
ModPagespeedEnableFilters elide_attributes
ModPagespeedEnableFilters trim_urls
ModPagespeedEnableFilters pedantic
#
# JavaScript
#
ModPagespeedEnableFilters combine_javascript
ModPagespeedEnableFilters canonicalize_javascript_libraries
ModPagespeedEnableFilters rewrite_javascript
ModPagespeedEnableFilters defer_javascript
ModPagespeedEnableFilters inline_javascript
#
# CSS
#
ModPagespeedEnableFilters rewrite_css
ModPagespeedEnableFilters combine_css
ModPagespeedEnableFilters move_css_to_head
ModPagespeedEnableFilters inline_css
ModPagespeedEnableFilters inline_import_to_link
ModPagespeedEnableFilters move_css_above_scripts
#
# Images
#
ModPagespeedEnableFilters inline_preview_images
ModPagespeedEnableFilters insert_img_dimensions
ModPagespeedEnableFilters rewrite_images
ModPagespeedEnableFilters recompress_images
ModPagespeedEnableFilters convert_jpeg_to_progressive
ModPagespeedEnableFilters resize_mobile_images
ModPagespeedEnableFilters sprite_images
ModPagespeedEnableFilters lazyload_images
ModPagespeedEnableFilters local_storage_cache
</IfModule>