The site is now running XF 1.1.0 B4 and is also taking advantage of APC caching.
EDIT: The sprite sheet versions of the smilies are now also being used. If you're looking for a quick & dirty query to switch to the sprite sheet versions after you upgrade to XF 1.1, check out this thread.
Upgraded to 1.1 b4 had to completely disable my custom style. Need some help, I want a dark style made using only the colour palette, no additional images or anything like that but I'm crappy using it. Anyone got a set of presets I could use.