Lower taxes are better, but that is simplistic. The government can kill the economy with high expenditures regardless of the tax rate, and the fruits of government decisions, rotten or juicy, do not impact the market for years thereafter.
The boom of the Reagan years was the product of the lean-and-mean nature of business during the late '70s and early 80's; not Reagan's decisions. Most major infrastructure developments take many years to run their course. The seeds for the recovery that took place during the Reagan years were in place before any of his budgets came into fruition.
After that, the expansion and bull market of the 80's and 90's was a by-product of technological development and the end of the cold wat; not anything that any administration did.