they are all exactly the same machine the top end one(elite) has the biggest hard drive 120gig,i think the lower priced ones dont come with hard drives or headsets for using online and i believe the controllers are the wired ones as apose to wireless
cracking machines
as for memory i have an elite an still have 82 gb left,you can always upgrade the hard drives later,but as they are now doing full games to download on to the hd the bigger the better if you would be interested in that