Hmmm...decisions, decisions.
Depends on what you want. Sounds like you miss certain distortion tones, so a dedicated pedal that delivers crunch could be in order. Otherwise you just gotta decide what you're looking for effect-wise.

Some of the most useful ones being: distortion (of course), chorus, eq, delay, reverb, and noise gate.

Alot of the other effects, phaser, tremelo, auto-wah, flanger, pitch-shifter, panner, rotary, and volume envelope, while fun to play around with, see a more limited use.

But try all of them out, you'll like some more than others, and some not at all. The bigger variety you like, the more a multi looks like the way. But it's not worth it if you're just gonna mainly use 2-3 settings.