Priority list if you want to make better beer:
1) Fermentation temp control (fermentation chamber, dual stage temp controller, heating source, cooling source)
2) Proper water chemistry (Ward Labs report on your water, understanding of water chemistry, a good pH meter, RO or distilled water, mineral/acid additions to water)
3) Proper amount of yeast (stir plate, stir bar, flasks)
4) Good recipes (recipe database here on HBT)
5) Control over carbonation (kegging system)
6) Quality ingredients (ingredients stored properly)
Other stuff, like a bigger BK or brew pumps or a fully automated electric brewery will make brewing easier and more enjoyable, but it won't make better beer.