well, the core has no HD cables included, and no hard drive. i'd go with the regular for just those 2 features, but if you don't have high def and you don't care about a hard drive go with the core, especially if the price drops by $100.
last November Amazon had a sale, 1000 core systems for $100. the site crashed for 15 min about 5 seconds past the time it was released, needless to say I didn't get one, so hearing from someone with a 360 would probably do you better.