I have a 60Gig HD I still have around 2GBs left on my Xbox. I gone from having a 20Gig to 60 because I used to play Phantasy Star Universe and it ate all my storage.

I am going to get a 120 soon since they are getting pretty cheap and with that storage should never be a issue with me, plus, I also play my PC so I guess i really never had much of an issue with it. ><