You mean for Step 2 CK? I'm going to use MTB 2 and probably 3 (since I hear the management portion of 3 is very good) and maybe case files. Probably not case files. It's going to a small portion of Step 2 I believe compared to all the medicine that will be on it.
For the OB/GYN Shelf - Case Files + Blueprints + UWorld + UWise.