[takeda]

MacPorts use /opt/local :)

[fit2rule]

And, interestingly, HomeBrew uses /usr/local "because Apple left it for us when they abandoned this whole mess" ..

[justincormack]

/use/local/bin has the big advantage that it is in the default PATH.

[therein]

I was about to say, I've seen /opt/local somewhere. :)

[drauh]

And Fink uses /sw. Which left me looking for some other place to dump stuff I compiled myself.