Can someone explain to me the difference between a regular Xbox 360, and the “Core System”?
The ads in the paper show an approximate $100 difference in price between the two. I’d like to pick one up once the price falls to the pre-release amount, but if I can save $100, I’m all over that.
Apparently the core system is the console + controller + Composite (not HD) wires to hook up to your (non HD) TV.
The regular version contains: The console, hardrive, controller, xbox live headset, HD wires to hook up to your hd tv, and an ethernet cable.
The hardrive looks like the most needed “extra” on that bundle.
And remember, they are speculating that the hard drive itself will retail for about $99 so it will be worth it to get the regular bundle.
How much cheaper were they before they were released 
It’s really not worth buying the Core System. The accessories included with the regular system are about $200 if purchased seperately (Hard drive: $99, wireless controller: $50, headset: $20, memory card (not needed with hard drive, but also not included with Core System): $20). The hard drive is needed to play original Xbox games, and you need either a memory card or hard drive to use Xbox Live.
Doesn’t the $400 bundle include a year of the XBOX Live service as well?
Think of the Core System as being “XBox 360 lite” its designed for those people who will only ever own three xbox games (two of which will be sports titles) and will rarely, if ever, go online with it.
I’m not saying thats a bad thing though - obviously if that’s what you’re after then go for it.
While we are on xbox 360 stuff - will it play all my old xbox games or only some of them? I have seen a few differing opinions on that
Some will play, others will not. In addition you will need to purchase the XBOX hard drive to play games from the last system.
From what I’ve read, it’s not 100% backwards compatible. The harddrive will be required for that, presumably to store system tweaks specific to each old title. Microsoft has said they intend to get all the old games working, but who knows? There’s a list of titles and their status on the 360 here.