+1 on the Phil Wood. I'm still running an original Phil Wood square-taper BB that came on an MTB I bought USED in 1987! I keep switching it from frame to frame and it keeps on running smoothly. They are crazy expensive and not nearly the lightest out there, but I think are very good long-term values.

I would conjecture that square-taper BBs would be more durable than newer styles, as the axle is essentially a solid block of metal and the bearing setup is pretty straightforward. I've also had very good experiences with higher-end Shimano square-taper BBs, like XT level (if you can still find them), and they are a lot cheaper than Phil BBs.