For our home wines, I have a EuroCave constant temp unit with sliding shelves. Holds about 225 bottles IIRC, problem with rack spacing is these fat NA Burg bottles are too big in diameter for single sliding shelves. But what I like about it is it is a constant temp unit, not a fridge. So when it gets cold in the winter, it works as a heat pump and keeps the temp steady.
Unless you are doing decade+ aging, I wouldn't worry about the diff between 55 or 60. Above 65 is not ideal, but not a crime. Rapid temp changes and low humidity are bad.
We have a quasi-basement since our home is built on a hillside - it stays very cool and constant temperature, I store a few cases down there just stacked in boxes.
Best storage racks depend if you have lots of similar/same bottles or lots of individual bottles that are different. Go to
www.wineenthusiast.com for some ideas. I think simple is best unless you are building a trophy room. I think this
style of cube with an "X" in the middle (sorry, can't post the flash picture) is very flexible, space efficient and economical. Would be very easy to make yourself.