Thinking of getting an Xbox. Is it a good idea to get the 250gb or the 4 gb. I am probably only going to be playing games.

Depends on what plan to do with it. With dlc, that 4gig is going to be eaten for breakfast. They basically upped it to 4gig for save games and small, small amounts of dlc. If you intend to get a lot of dlc, like guitar game songs or additional game scenarios or extra game characters, you'll need the space. Especially if you plan to try out demos or even install games to the drive. ESPECIALLY if you install games to the drive.

Take it from me. If you plan to use the xbox on a regular basis... install games to the drive.

Couldnt he upgrade the hard drive himself later?  Wouldnt this be a more cost effective approach?

True. You CAN upgrade the drive yourself... but you need a specific brand of drive and it has to be flashed very particularly. Not just any ol' Seagate or whatever will do. Glorious plan of M$, despite how awesome the 360 is. If you want to upgrade the external drive, you have to actually buy the drive and the unit it's enclosed it for an outrageous amount of money versus what it's actually worth.

It's honestly better to buy a new 250gig unit or a used 120gig unit. Keep it away from carpet, make sure it's laying flat while it's on and airflow/cooling shouldn't be a problem. I had an elite, but it died, so I got a arcade unit and ported the existing drive onto it and actually saved myself a bit of money.

And that ability to use external flash drives? Sully's absolutely right. You can use the usb ports, but you're limited to 16gigs. That's even WITH a usb flash drive that's larger than 16gig. Stupid M$ gaming division. Bah!