Easy, LA-2A 90% of the time, the 1176 the other 10%
Even both in some combos works great.
EDIT: Maybe I should elaborate on that before I get reamed. I frequently run vocals through the LA-2A to tape. I set it so that the needle is just barely moving, that way it just catches the very tips of the peaks, kinda smoothing things out. Then, if I want to make a vocal fuller, I'll duplicate the track, then run it through the 1176 with a good amount of squishing going on, and bring that up underneath the original vocal.