Equipment for all grain is much of a personal preference and the types of beers you brew. I am in 1/2 bbl converted kegs for my mash tun and boil kettle...and now have a super fancy HLT from Stout Tanks. I have never used a cooler. I do 10-12 gallon batches, but I don't often do big beers (above 1.085), nor use a lot of sticky adjuncts, so I don't have problems with stuck mashes and low efficiencies....I can direct fire any of my tanks and mostly interchange them if I ever needed (in case of failure).
I started with one keg kettle and a 5 gallon pot for my HLT and always needed extra water for sparging and was always transfering wort all around my brewery. Built my system one piece at a time (well after it was painfully evident that I needed the next piece of equipment). In this manner, I was able to save for good equipment and over buy (bigger and slightly better than I deserve) and look for deals....but it is as I said, a personal preference. Good beer can be made from the most simple of equipment...and really bad beer can be made anywhere.