[Sooper]

Go for the hard drivey one. Overall better build quality and lifesan, dunno why like, just is.

Does the other one not have a hard drive at all? How do you save games?

Confusing. Will most likely get the hard drive one.

Whats the deal with the HD DVD add on thing?

Are we talking about the Xbox Elite that is due to come out over here or the original Xbox 360? If you dont have a Hard Drive you cant go On-line and you wouldnt be able to store scores achievements etc other than with a Memory card that aint gonna hold much. I had to buy my 360 with no Hard Drive as they were all sold out at the time but i added one shortly afterwards which was no probs.
The HD DVD thing is supposedly very good and well worth the money but it has another huge power brick to run it and is supposed to run hot and loud which could be a tad annoying if you are watching quiet parts to a film! Im gonna get an Elite when they are released because of the whole High Def thing which on this model can use 1080i and P (I think?) so better overall picture and sound quality. Microsoft yet again fucked the original 360 owners!