I have to agree with PLV on this, and as much as it pains me to say so (as I'm a HUGE Tanker fan), the "best" "tank" for farming is a brute. That said there is a certain pleasure in running the fire farm maps with a Tank, just whittling down the bosses can be a pain. I've yet to do this (dang, another project to finish...), but I'd build the Fire/S/L protection in (Def+Res) then look at procing your ST/Big Damage ST attacks for taking down the bosses+. You normal build AoEs+Burn should handle everything else.