when buying an xbox ..........?

You'll want the Pro 60 Gigabyte system. You can get the bundle from Amazon for $299 out the door with free shipping. Don't get the Arcade and you can spend an extra $100 for an Elite, but you'll probably never need the extra hard drive space. I've got a 20 Gigabyte and it holds everything from downloaded games to videos.

The bundle above comes with two games. Lego Indiana Jones (Very cool) and Kung Fu Panda.

If your buying a brand new xbox go with the 60gig. Not way to much but not way to little like the 20gig. if not and your buying another hard drive. Depending on what you will do, if you just want one for like movies or whatever you can get another 20gig, or if you are wanting to save games with the new dashboard feature to cut down load times then a 120gig would be best, because games take like 4.7 gig

It all depends on what you are going to be using it for. If you just want to save games and stuff from the Marketplace then the Pro with 60 gig HDD is fine. Now if you want to install your games and try to quicken load times and playability then get the Elite with the 120 gig HDD.