Hi,
If you are about to go live, have you considered putting the DSEFU mod on? Is really good for new shops to get you up the Search Engines and saves you having to do the html catalog each time:
http://www.safetynetweb.com/X-Cart-Mods-c-1.html
Also, for better SEO, you should consider moving the site from the subfolder /xcart to the root. Easier for search engine spiders for a start.
Cosmetically (hmm maybe need another word here!), the one thing I would do is centre the page - looks like you designed for 800 resolution, this would then look better in higher resolutions.
Hope that helps as well.