Re: What pedal would give me some "synth" sounds?
I look at it from the standpoint of an analog synth.
Compressor to create a strong signal
Octaver/harmonizer (POG/Whammy) to generate more tones
Fuzz/Distortion to generate more harmonics (both of which to be filtered downstream)
Volume pedal/tremolo for VCA effects
Wah/auto filter for VCF effects
Phase Shifter and Chorus for doubling and swirling phase
Delay and reverb for lush textures
I use my ZVex seek Trem and seek wah for arpeggiated type chopped/patterned lines and tones.
I think today a lot of pedals will do many of these things for you. Crap, a Digitech Synth Wah can get you analog tones and one of the new digital pedals (EHx, Earthquaker) will probably get you close for digital synth tones.
The final piece of the pie is playing like a synth. Block chording, etc. rather than strumming.