If we're talking pedalboard units, not just effects:
Xotic AC Booster. My fave pedal. Adds warmth to other drive pedals, cleans up nicely, and gives me that smooth, fat lead sound.
MXR Carbon Copy. Finally a warm delay pedal that doesn't hog too much of the spotlight.
TC Electronics Polytune. Because tuner, that's why.
Boss CE-2. I've had this one for years. I don't use chorus very often, but when I do, I really like the simple settings and sound of this old-timer.
EP Booster clone. Handmade by a local builder. This one surprised me. I fell in love after a few seconds, but I still can't pinpoint what it is about it that I dig. It just... improves everything.
I also have a Rat clone that I'm trying out. Good results so far, but I can't decide if it's THAT important to include on the list. Also have a standard Crybaby that I never use, a revolving door of fuzz boxes (currently a Fulltone '69), and a Mooer Blues Mood that I'll go pick up tomorrow.