How much do you want to spend?
For under $200 a set I like Carolinas, mine have survived 4.5 years of incredibly hard use including mining, HVAC work, welding, and just general wear and they are comfortable to wear for 12+ hours a day.
If you are willing to spend closer to $500 look at a set of Nicks or Whites custom boots, a guy I worked with just started thinking about having his rebuilt after 6 years of mining and I have most of the guys I know wearing them have gotten a minimum of 2-4 years out of them before a rebuild. Personally I am going to buy a set of 10" Nicks loggers or Linemans with a composite safety toe for my next set of boots.