With most of my chars ray of enfeeblement is a minor nuisance, but I have a low str build monk (all dex and wis) that when I get hit with it I immediately become encumbered and:
AC goes from 30 to 18 (become uncentered, loose wis and dex bonuses)
Damage goes from 1D10 + 5 to 1d4 +0 (loose monk unarmed damage)
Move speed gets cut ~ 30% (uncentered)
attack speed gets cut ~ 30% (uncentered)
and of course I can't jump or tumble.
My monk goes from Kick butt to butt kicked in no time and if it happens with more than about 4 monsters in the room its like a ray of death. I note that the ray is a no save spell, but there are deathblock outfits, do they work on the Ray?