Refrigerator enclosure dimensions
Why not build it around a specific model?  Refrigerators are made to be long-lasting, almost like a fixture, not something that changes frequently and needs a universally-sized nook.  If you pick a fridge now, you can get its exact dimensions and ventilation clearance requirements and build your enclosure to those specs.  What if you picked "standard" dimensions now, and then select your dream refrigerator only to find it won't fit?