Why I'm looking forward to the remakes...
The Halo 2 Anniversary section is obviously the key selling point of this disk, and for those of us who don't use Windows, Halo 2 Anniversary will be an excellent throwback to the game that started Halo multiplayer. I didn't have Xbox Live until 2010, so I only got to play the game when I was round a friend's house. It was an awesome game and for people who never got the chance to play it, now they can with dedicated server support, 60fps and 1080p HD!
Why I'm looking forward to the Halo 5 Beta...
Halo 4 was a mixed bag; it was a really fun game but it didn't have the replay value of Halo 3. I thought there was considerably more good than bad in Halo 4 whilst others severely disliked it. But I thought it was a decent first attempt. But now that they have heard fan feedback and have a new piece of hardware to work on, I think Halo 5 is going to be great (I'm not saying it will be, just saying how I think it'll be). They have shown that they are listening to the fanbase (they asked for Halo 2 Anniversary, and they give us this collection!) and that they are aiming to please them. They even admitted that Halo 4 wasn't as good as it could've been.
It's a tough choice but I think I'm more looking forward to the Halo 2 Anniversary. Also, don't forget about Halo: Combat Evolved being playable online! On Xbox, the only way to play Halo: Combat Evolved online was on Xbox Connect as Xbox LIVE didn't exist when the game was made (Xbox LIVE first launched in 2002) so this will be the first time that the multiplayer would be playable on Xbox LIVE!