if u want to save your progress because a hardrive saves your progress through out the game
as long as you have a large enough flash drive, or memory stick, you can save all your progress onto that.
maps, screenshots, ect.
yep.
NO, you need a flash drive for everything.
you will need a hard drive and invite people.
Yes... but you need a Hard drive. And there are no achievements!
you need an xbox hard drive
no but you need a hard drive to view films in threatre
Yes, you do.
yes
No, you mainly need a HDD ( Hard Drive ) for saving film clips and installing the game, which is optional.
You need to do forge to create your maps in halo 3
Yes you do and you also need an Xbox LIVE account.
you need xbox live
No, that would be silly.