havent played in a long time getting back into it but didnt know witch to get
You can’t buy one without the other. Halo 3: ODST is Halo 3 mutliplayer, custom games, forge and theater, then a second disk composed of ODST campaign, firefight, and then ODSTs theater.
Regular Halo 3 edition: Contains Campaign and multiplayer with the shipped maps.
ODST: Gives you ODST campaign, firefight and Halo 3 multiplayer with ALL maps on the disc. (Note: Halo 3s campaign is NOT in the ODST set)
Get both? 
Halo 3 was better in my opinion. I did love firefight in ODST but there’s no matchmaking.
> You can’t buy one without the other. Halo 3: ODST is Halo 3 mutliplayer, custom games, forge and theater, then a second disk composed of ODST campaign, firefight, and then ODSTs theater.
You get both and one is fun FF with friends and one is an amazing MM game with friends its a blasy blast
Both are amazing games!
No Halo collection is complete without them.
> Halo 3 was better in my opinion. I did love firefight in ODST but there’s no matchmaking.
Agreed.really liked FF on ODST.
I liked both.
As they both used the same engine and both also had compelling storylines, I liked both. Its the only occasion where graphics between two games matched up.
Although the events of ODST occur midway through Halo 2s storyline, another view of the same events is very appealing.
Get ODST if you want to play Halo 3 online and if you want to play the ODST campaign.
Get Halo 3 if you want to play the Halo 3 campaign.