Hello
I would suggest to keep away from tide integration of x-cart with word press, mainly, for performance reasons.
You would essentially be loading up both applications every time you access WordPress, and while WordPress is very fast and light, X-Cart can be very server resource hungry.
Server load means slower site, which is not good.
But that of course leaves you without cart content/status in WordPress.
The easiest way is to have wordpress theme matching the x-cart theme while running WordPress blog completely independent from your X-Cart.
here are couple of examples of that approach:
WordPress:
http://www.carttemplates.com/
X-Cart:
http://www.carttemplates.com/mods/
WordPress:
http://www.outdoorphotogear.com/blog/
X-Cart:
http://www.outdoorphotogear.com/store/
And if you want to have recent blog posts on your X-Cart pages you can use this free mod here
http://www.carttemplates.com/mods/xcart-wordpress-rss-feed-integration.html
Hope that helps!