Although Halo: 4 isn’t due out until November of this year, you might want to start considering upgrading your Xbox 360′s memory capabilities. Microsoft announced that not every ‘out-of-the-box’ Xbox 360 console will be able to play the coveted game.
If you are planning on playing the multiplayer version of the title (and really who isn’t) then you will need an adequate hard drive or an 8GB flash drive in order to run it.
You will need the flash drive if you own a 4GB Xbox 360, a Core unit or an Arcade unit. Microsoft states:
At a minimum, you’ll need at least an 8GB USB Flash Drive or an Xbox 360 Hard Drive to play Multiplayer mode in Halo 4. For an optimal experience playing with an Xbox 360 Hard Drive is highly recommended. For Xbox 360 4GB, Arcade and Core consoles, the Xbox 360 Hard Drive is sold separately.
You can usually find the flash drives pretty cheap, you can even get an 8GB or 16GB version. Here are a few that Amazon already has on sale. If you rather just upgrade your hard drive and be done with it, you can pick up the 320 GB hard drive for around $100 as well.