I noticed a significant performance gain on my virtuemart store when switching from Apache to Litespeed Enterprise. I use to have loading times of 16 seconds on SSL. Now my load times are less than 6 seconds :). Also PCI Compliance is so easy to maintain without Apache. I also used a CDN From cdn77.com for loading my images, and that seems to have helped a bit.
https://www.deltaguns.com (https://www.deltaguns.com)
Well, if I look at your frontpage with the Firefox plugin 'Firebug' enabled, Firebug's 'Net' tab still shows me 18 - 20 seconds for the page to be loaded completely. I think this is primarily due to your large slideshow blocking other images to load for a while (Browsers are loading images one after another). Also Firebug shows a javascript problem in your slideshow:
$Gavick is not defined
Line 1500
Also you are loading at least two different javascript versions:
...//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js
.../modules/mod_susnet_likebox/js/jquery-1.7.2.js
If you want to avoid javascript conflicts, only one jQuery library should be loaded..