Halo is only on the Xbox or the Xbox live.
The only way to get map packs is buy xbox live. so yes
Halo is an xbox exclucive only, this means that it can only be played on xbox.
Get Xbox Live on your account then in Halo Reach click "Matchmaking" from the Main Menu.
No currently Halo: Reach will only be for the Xbox 360.
If you only have sliver membership, but you are still connected to Xbox live, you can do some of the challenges.
Yes, and only sold for the Xbox.
you can,t
none they all reqire xbox live
by doing achievements so no not only in Xbox live but Xbox live gives you more finishing and winning a match will give you a nice amount
no... only if you want to play online matchmaking
no it can be played offline with custom rules including invincibility