While Halo 3 had some customisability when it comes to armour and colouring but it looks like Halo Reach is going to up the anti in a big way.
Note these are just the initial pieces; unlocking higher levels through playtime will grant you access to new components. Interesting that Master Chief, Cortana and Sgt. Johnson are present. Yeah that is Cortana, seems like an odd choice to me.

Also available are Avatar unlockables in the shape of 5 of Noble Teams helmets.
Noble Six's helmet, will only be available to attendees of Comicon, PAX and GamesCom.

__________________

Always love customizability, and it looks like they've definitely stepped it up a notch from H3.
Also recognize that dude from ODST, errr whats-his-face lol.
Still love how you can play as your spartan in campaign