[Greenbuilding] Which caulk

[Jefro]

I appreciate the discussions on this list about caulking seams to 
prevent air infiltration.  We are finishing up the first-floor joists 
this week, and while the plumber does the underfloor I would like to 
spend some quality time sealing the underfloor seams between foundation 
and sill, between sill and rim joist, and in all butt joints.


The question now is---which of the bewildering assortment of caulks 
should I use?  The contractor recommends using one with a polyurethane 
base.  I would prefer that to acrylic or (ugh) vinyl.  Any recommendations?