Following on from some experiments with Page Speed and YSlow plugins for Fire Fox I have modded my .htaccess file to include the following
RewriteEngine on
FileETag none
<FilesMatch "sleight_js.php$">SetOutputFilter DEFLATE
ExpiresActive on
ExpiresDefault "access plus 2 months"
</FilesMatch><FilesMatch "\\.(js|css)$">SetOutputFilter DEFLATE
</FilesMatch><FilesMatch "\.(gif|jpg|png|js|css|ico)$">ExpiresActive on
ExpiresDefault "access plus 2 months"
</FilesMatch>
Briefly what happens is slight_js.php now gets gzipped
all js and css files get gzipped before delivery
all gif,jpg,png,js,css and ico files get a long expiry date which means the browser caches them
When moving from page to page there are some considerable time savings.
Next job is to minify the javascript and css files in the theme and in plugins. Then we'll look at the order of delivering the js and moving as much as possible to the end of the page rather than the footer