If they aren't going to be getting a bunch of Downloadable Content, and don't install the games directly on the hard-drive like some people do, then 4 gigs should be plenty for 3 games.  (I used to keep my whole profile on a 256 MB memory card on one of tyhe older 360's, but had to switch to the Hard Drive when I started to buy DLC.  Installing the games is recommended if the system will be on a lot, as I'm told it helps with overheating, but they have drastically reduced overheating issues with their newer models so that shouldn't be necessary anyway.  If you are willing to shell out extra money in the future, you can always upgrade the size of the hard-drive later, although I am not possitive how you would go about transfering gamer-profiles if you did that...

-Twi

Yeah, once you get an x360 HD installing is the way to go.  It cuts off the noise from the DVD drive while playing.

Transferring gamer profiles and such is easy in the system menus.  I no longer have a 360 so I can't walk you through it, not that you'd need me to yet anyway.

It'd probably be fine, though I can't guarantee anything.

I had to flash my laptop harddisk using hddhakr program but once that was done I was able to use the drive in my exbox. It went from a 160 to a 120 but it works. Free drive for me.

Now I can play pretty much anything.