After a TON of confirming leaks Microsoft unveiled the MCC will be released on November 11, 2014 featuring Halos 1-4. Watch the video here featuring Prophet from Crysis! (Unconfirmed)
Bigger news is the details of the multiplayer. 343i is keeping in the exact same multiplayer from Halo 2 and adding in playlists for other games.
Also there will be 100 mutliplayer maps running at 1080p and 60fps bringing all the maps from Halo 1-4.
The MCC will include 4,000 gamerscore points because Halo is awesome!
Halo Nightfall a live action production by Ridley Scott will be included in the MCC in its entirety on November 11.
In December Halo 5 Guardians Beta will be accessable to individuals that have purchased the MCC.
Also because they just kept saying it, HOSTED SERVERS FOR MULTIPLAYER.