I'm am on the hype train for CQB and Operator.
Mark V Delta or CQB. I'm a bit sad there's no 'Gen 1' ODST helmet (yet). It'd certainly be better than the white-lined, cheek tumors of Helljumper. The Reach base ODST helmet would be perfect.
The Recon Gen 1. Many many years ago I achieved all the vidmasters and was excited to gain Recon in Halo 3. Now that 343 is adding the Reach's version which is very similar to Halo 3, I am ecstatic.