OT: Xbox 360

[Longman]

OK so Sainsbury's offer of an Xbox for £99.97 was too much for me and I
impulse bought one last night ( I mean even Amazon are selling them for
£129.99! ).  Question I have — and I'm sure somebody here will know the
answer! ;-) — is what do I lose out on from not getting the premium
version (which was out of stock, they had sold three that day and the
offer expires Sunday with only one more delivery until then) ?  And more
importantly what impact is there from what I lose?  And can I just buy
the stuff separately later on?

Haven't owned a console since the PS1 though the weather is so crappy I
thought it might make a winter spent indoors more fun.