I'll go out on a limb and say the Seamaster Calendar. Looks like a sharp example Closer photos and in natural light please!
OOOooo... hard for me to choose between the Constellation and the Seamaster Calendar. I really like both of those models.
Constellation with Calendar in close 2nd. Can you post some closer pictures? What are you wanting to add next?
The Omega Constellations with pie pan dials are my very favorite Omegas of all, but that Seamaster Calendar is awfully nice. Wouldn't mind adding one just like it to the watch menagerie. That's saying a lot as I don't generally care for a date feature. Anytime the date appears anywhere beside the 3 o'clock position is a plus for watch appearance to me.
Your Seamaster Calendar is an absolute cracker, the six o’clock date window gives it a lovely symmetry. What reference is it? The pie pan is none too shabby either. Congrats.