wolverine durashocks work for me. i'm on my 2nd pair in 12 years, and they are very comfortable, and fairly waterproof, in case you have to slop around a muddy jobsite. one word of advice tho', it takes a long time to "break them in"! i carried an old pair of boots with me for 3 or 4 months, and changed sometimes during the day, if my feet started hurting. dont know why it takes so long to break in wolverines, but prolly because they are made so "heavy-duty" and very stiff, when new.
i clean mine once a month and give 'em a good massage with mink oil. mine have lasted on average, about 6 years before they need replacing.