Having bought one I found, like other customers there was a shortfall in capacity eg: if it was a 20GB you bought then when you fit it and prepare to format it shows that you only have 13.9GB of free space
The seller i bought from has received a lot of negative feedback for one, and I am sure there are other sellers in a similar position. It would, however, only have taken them a few extra minutes of research and clarification to prevent this.
The "problem" as such is Microsoft actually being helpful before they ship the items initially.
Put simply there are THREE pieces of software installed for use in a LIVE situation
1 To allow updates for the X Box software when available
2 To allow updates for the X Box Live games when playing online
3 A CD archive to assist when ripping your music to the hard drive
Now we are aware of what is on the drive we have no problem in fact have already used the archive.
However a note to sellers: Please make your potential customers aware that this is a benefit to them and save yourself from disappointed buyer e-meils and feedback. You never know it may even increase sales!