My favorite ambient pedals. Boss PN-2 Pan/Trem, Alesis Ampliton Pan Trem, Boss DD-20 (23 seconds of stereo delay, feedback knob at full acts as infinite hold with no regeneration on itself, and you can switch to the next mode in a different time and the last sound set keeps going and going to wherever you had the feedback knob when you left...), Boss PS-3 Pitch Shifter, Boss ODB-3 (the key here is the wet/dry knob...), Small Stone.
Oh and of course - eBOWS, cello bow, slides, Rosin (seriously put Rosin on anything!...just try it...), TV Remotes, Piezo on the headstock.
Reverb I'm lost on. I have a RV-5 right now only because of it having stereo ins/outs. I'm fairly happy with the modulate setting.
Regarding the PDS series. Does anyone know if you can extend the loop time on the PDS 2000's? I recently came across two of these. I would like to make them longer and lo-fi, or at least one of them.